<PAGE>   1
                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549


                                    FORM 10-Q


[ X ]           QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d)
                    OF THE SECURITIES EXCHANGE ACT OF 1934

                  For the Quarterly period ended MARCH 31, 1998

[   ]           TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d)
                     OF THE SECURITIES EXCHANGE ACT OF 1934

              For the Transition period from              to
                                             ------------    -------------

                          Commission file number 1-1098


                              COLUMBIA ENERGY GROUP
             ------------------------------------------------------
             (Exact Name of Registrant as Specified in its Charter)


                Delaware                                   13-1594808
      -------------------------------                  -------------------
      (State or other jurisdiction of                    (IRS Employer
       incorporation or organization)                  Identification No.)


  12355 Sunrise Valley Drive, Suite 300, Reston, VA        20191-3420
  -------------------------------------------------        ----------
     (Address of principal executive offices)              (Zip Code)



        Registrant's telephone number, including area code (703) 295-0300


     Indicate by check mark whether the registrant: (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days. Yes  X   No
                                             -----   ------


     Indicate the number of shares outstanding of each of the issuer's classes
of common stock, as of the latest practicable date: Common Stock, $10 Par Value:
55,523,255 shares outstanding at March 31, 1998.


<PAGE>   2




                     COLUMBIA ENERGY GROUP AND SUBSIDIARIES
                           FORM 10-Q QUARTERLY REPORT
                      FOR THE QUARTER ENDED MARCH 31, 1998

                                TABLE OF CONTENTS


<TABLE>
<CAPTION>
                                                                                  Page
                                                                                  ----
<S>           <C>                                                                <C>
PART I         FINANCIAL INFORMATION

Item 1         Financial Statements

                  Statements of Consolidated Income                                 3

                  Condensed Consolidated Balance Sheets                             4

                  Consolidated Statements of Cash Flows                             6

                  Consolidated Statements of Common Stock Equity                    7

                  Notes                                                             8


Item 2         Management's Discussion and Analysis of
                  Financial Condition and Results of Operations                     9


Item 3         Quantitative and Qualitative Disclosures About Market Risks         23


PART II  OTHER INFORMATION

Item 1         Legal Proceedings                                                   24

Item 2         Changes in Securities and Use of Proceeds                           24

Item 3         Defaults Upon Senior Securities                                     24

Item 4         Submission of Matters to a Vote of Security Holders                 24

Item 5         Other Information                                                   24

Item 6         Exhibits and Reports on Form 8-K                                    24

               Signature                                                           25
</TABLE>




                                       2
<PAGE>   3
                         PART 1 - FINANCIAL INFORMATION
                          ITEM 1 - FINANCIAL STATEMENTS


Columbia Energy Group and Subsidiaries
STATEMENTS OF CONSOLIDATED INCOME (unaudited)
<TABLE>
<CAPTION>
                                                           Three Months
                                                          Ended March 31,
                                                      ------------------------
                                                       1998             1997
                                                      --------        -------- 
                                                 (millions, except per share amounts)
<S>                                                   <C>             <C>
NET REVENUES
     Gas sales                                        $1,593.3        $1,308.0
     Less: Products purchased                          1,212.9           896.7
                                                      --------        --------

     Gross Margin                                        380.4           411.3
                                                      --------        --------
     Transportation                                      161.2           148.5
     Production gas sales                                 17.4             5.3
     Other                                                63.5            63.0
                                                      --------        --------
Total Net Revenues                                       622.5           628.1
                                                      --------        --------

OPERATING EXPENSES
     Operation                                           184.4           198.9
     Maintenance                                          21.7            24.6
     Depreciation and depletion                           73.2            71.2
     Other taxes                                          89.0            76.8
                                                      --------        --------
Total Operating Expenses                                 368.3           371.5
                                                      --------        --------

OPERATING INCOME                                         254.2           256.6
                                                      --------        --------

OTHER INCOME (DEDUCTIONS)
     Interest income and other, net                        2.3            14.3
     Interest expense and related charges                (41.6)          (40.3)
                                                      --------        --------
Total Other Income (Deductions)                          (39.3)          (26.0)
                                                      --------        --------

INCOME BEFORE INCOME TAXES                               214.9           230.6
Income Taxes                                              67.4            67.9
                                                      --------        --------

NET INCOME                                            $  147.5        $  162.7
                                                      ========        ========

EARNINGS PER SHARE OF COMMON STOCK                    $   2.66        $   2.94

DIVIDENDS PAID PER SHARE OF COMMON STOCK              $   0.25        $   0.15

AVERAGE COMMON SHARES OUTSTANDING (thousands)           55,511          55,332
</TABLE>


The accompanying Notes to the Consolidated Financial Statements are an integral
part of these statements.


                                       3

<PAGE>   4
                         PART 1 - FINANCIAL INFORMATION
                         ITEM 1 - FINANCIAL STATEMENTS

Columbia Energy Group and Subsidiaries
Condensed Consolidated Balance Sheets

<TABLE>
<CAPTION>
                                                                  As of
                                                         --------------------------
                                                          March 31,    December 31,
                                                            1998           1997
                                                         -----------   ------------
                                                          (unaudited)
ASSETS                                                          (millions)
<S>                                                        <C>          <C>
Property, Plant and Equipment
    Gas utility and other plant, at original cost          $ 7,404.3    $ 7,368.9
    Accumulated depreciation                                (3,533.7)    (3,481.5)
                                                           ---------    ---------
    Net Gas Utility and Other Plant                          3,870.6      3,887.4
                                                           ---------    ---------
    Gas and oil producing properties, full cost method         671.3        660.2
    Accumulated depletion                                     (205.6)      (196.0)
                                                           ---------    ---------
    Net Gas and Oil Producing Properties                       465.7        464.2
                                                           ---------    ---------

Net Property, Plant and Equipment                            4,336.3      4,351.6
                                                           ---------    ---------

Investments and Other Assets                                    88.3         85.2
                                                           ---------    ---------

Current Assets
    Cash and temporary cash investments                         27.2         28.7
    Accounts receivable, net                                   848.3        868.5
    Gas inventory                                               50.8        226.8
    Other inventories - at average cost                         33.6         35.6
    Prepayments                                                 94.8        107.7
    Regulatory assets                                           66.0         64.6
    Underrecovered gas costs                                    17.0         41.4
    Deferred property taxes                                     58.9         80.8
    Exchange gas receivable                                    222.5        189.0
    Other                                                       46.3         64.6
                                                           ---------    ---------

Total Current Assets                                         1,465.4      1,707.7
                                                           ---------    ---------

Regulatory Assets                                              390.8        400.9
Deferred Charges                                                82.1         66.9
                                                           ---------    ---------

Total Assets                                               $ 6,362.9    $ 6,612.3
                                                           =========    =========
</TABLE>


The accompanying Notes to the Consolidated Financial Statements are an integral
part of these statements.



                                       4

<PAGE>   5
                         PART 1 - FINANCIAL INFORMATION
                          ITEM 1 - FINANCIAL STATEMENTS


Columbia Energy Group and Subsidiaries
CONDENSED CONSOLIDATED BALANCE SHEETS

<TABLE>
<CAPTION>
                                                                     As of
                                                          ---------------------------
                                                           March 31,     December 31,
                                                             1998            1997
                                                          --------        --------
                                                          (unaudited)

CAPITALIZATION AND LIABILITIES                                    (millions)
<S>                                                       <C>             <C>
CAPITALIZATION
     Common stock equity                                  $1,926.2        $1,790.7
     Long-term debt                                        2,003.4         2,003.5
                                                          --------        --------
Total Capitalization                                       3,929.6         3,794.2
                                                          --------        --------

CURRENT LIABILITIES
     Short-term debt                                          22.0           328.1
     Accounts and drafts payable                             447.4           536.7
     Accrued taxes                                           162.3           140.9
     Accrued interest                                         66.2            29.4
     Estimated rate refunds                                   70.3            68.4
     Estimated supplier obligations                           73.9            73.9
     Transportation and exchange gas payable                  95.9            89.2
     Overrecovered gas costs                                  87.3            84.6
     Other                                                   322.0           367.0
                                                          --------        --------
Total Current Liabilities                                  1,347.3         1,718.2
                                                          --------        --------

OTHER LIABILITIES AND DEFERRED CREDITS
     Deferred income taxes, noncurrent                       635.5           618.4
     Investment tax credits                                   35.2            35.6
     Postretirement benefits other than pensions              99.0           148.8
     Regulatory liabilities                                   63.5            41.3
     Other                                                   252.8           255.8
                                                          --------        --------
Total Other Liabilities and Deferred Credits               1,086.0         1,099.9
                                                          --------        --------

TOTAL CAPITALIZATION AND LIABILITIES                      $6,362.9        $6,612.3
                                                          ========        ========
</TABLE>



                                       5
<PAGE>   6
                         PART 1 - FINANCIAL INFORMATION
                          ITEM 1 - FINANCIAL STATEMENTS

Columbia Energy Group and Subsidiaries
Consolidated Statements of Cash Flows (unaudited)
<TABLE>
<CAPTION>
                                                                    Three Months
                                                                   Ended March 31,
                                                                --------------------
                                                                  1998       1997
                                                                --------   -------
                                                                    (millions)
OPERATING ACTIVITIES
<S>                                                             <C>         <C>   
   Net income                                                   $ 147.5    $ 162.7
   Adjustments for items not requiring (providing) cash:
      Depreciation and depletion                                   73.2       71.2
      Deferred income taxes                                        18.5      (14.1)
      Earnings from equity investment, net of distributions        (0.5)       0.3
      Other - net                                                  (3.2)      (6.0)
                                                                -------    -------
                                                                  235.5      214.1
                                                                -------    -------
   Change in components of working capital:
      Accounts receivable                                          (0.8)    (128.3)
      Gas inventory                                               176.0      232.2
      Prepayments                                                  12.9        8.8
      Accounts payable                                            (52.7)    (142.2)
      Accrued taxes                                                21.4       51.3
      Accrued interest                                             36.8       36.0
      Estimated rate refunds                                        1.9       (2.0)
      Estimated supplier obligations                                 --      (37.1)
      Under/Overrecovered gas costs                                27.2      172.2
      Exchange gas receivable/payable                             (25.2)     (58.4)
      Other working capital                                        (1.2)       7.5
                                                                -------    -------
Net Cash from Operations                                          431.8      354.1
                                                                -------    -------
INVESTMENT ACTIVITIES
   Capital expenditures                                           (70.5)     (60.2)
   Other investments - net                                         (6.9)      (8.6)
                                                                -------    -------

Net Investment Activities                                         (77.4)     (68.8)
                                                                -------    -------
FINANCING ACTIVITIES
   Dividends paid                                                 (13.8)      (8.3)
   Issuance of common stock                                         2.0        4.2
   Issuance (repayment) of short-term debt                       (305.3)    (250.0)
   Other financing activities                                     (38.8)     (15.7)
                                                                -------    -------
Net Financing Activities                                         (355.9)    (269.8)
                                                                -------    -------
Increase (decrease) in Cash and Temporary Cash Investments         (1.5)      15.5
Cash and temporary cash investments at beginning of year           28.7       49.8
                                                                -------    -------
Cash and temporary cash investments at March 31 *               $  27.2    $  65.3
                                                                =======    =======

Supplemental Disclosure of Cash Flow Information
   Cash paid for interest                                           3.8        3.0
   Cash paid for income taxes (net of refunds)                      0.6       (9.6)
</TABLE>




The accompanying Notes to the Consolidated Financial Statements are an integral
part of these statements. 

* The Corporation considers all highly liquid short-term investments to be cash
  equivalents.


                                       6


<PAGE>   7


                         PART 1 - FINANCIAL INFORMATION
                   ITEM 1 - FINANCIAL STATEMENTS (continued)




Columbia Energy Group and Subsidiaries
Consolidated Statements of Common Stock Equity


<TABLE>
<CAPTION>
                                                            As of
                                                  ----------------------------
                                                   March 31,      December 31,
                                                     1998             1997
                                                  ----------      -----------
                                                  (unaudited)
                                                          (millions)
<S>                                                <C>             <C>
COMMON STOCK EQUITY

Common stock, $10 par value, authorized
   100,000,000 shares, outstanding 55,523,255
   and 55,495,460 shares, respectively              $  555.2        $ 554.9

Additional paid in capital                             755.4          754.2

Retained earnings                                      616.4          482.7

Unearned employee compensation                          (0.9)          (1.1)

Accumulated Other Comprehensive Income:
   Foreign currency translation adjustment               0.1             --
                                                    --------       --------

TOTAL COMMON STOCK EQUITY                           $1,926.2       $1,790.7
                                                    ========       ========
</TABLE>

The accompanying Notes to the Consolidated Financial Statements are an integral
part of these statements.


                                       7


<PAGE>   8

                         PART 1 - FINANCIAL INFORMATION
                   ITEM 1 - FINANCIAL STATEMENTS (continued)


Columbia Energy Group and Subsidiaries

NOTES

1.       Basis of Accounting Presentation

         The accompanying unaudited condensed consolidated financial statements
         for the Columbia Energy Group (Columbia) reflect all normal recurring
         adjustments which are necessary, in the opinion of management, to
         present fairly the results of operations in accordance with generally
         accepted accounting principles.

         The accompanying financial statements should be read in conjunction
         with the financial statements and notes thereto included in Columbia's
         1997 Annual Report on Form 10-K. Income for interim periods may not be
         indicative of results for the calendar year due to weather variations
         and other factors. Certain reclassifications have been made to the 1997
         financial statements to conform to the 1998 presentation.

2.       Settlement of Retiree Benefit Obligation

         In March 1998, trusts established by Columbia purchased insurance
         policies that provide both medical and life insurance with respect to
         liabilities to a selected class of current retirees. This resulted in a
         settlement of $152.1 million of Columbia's obligation and a gain in the
         amount of $46.7 million, pre-tax. This gain is reflected in the
         financial statements as a $23.1 million reduction to benefits expense,
         and a $23.6 million liability by certain rate regulated companies.

3.       Earnings Per Share

         Financial Accounting Standards Board Statement of Financial Accounting
         Standards No. 128, "Earnings Per Share" (SFAS No. 128) requires dual
         presentation of Basic and Diluted earnings per share (EPS) by entities
         with complex capital structures and also requires restatement of all
         prior-period EPS data presented. Basic EPS includes no dilution and is
         computed by dividing income available to common stockholders by the
         weighted-average number of common shares outstanding for the period.
         Diluted EPS reflects the potential dilution if certain securities are
         converted into common stock.

         Under the requirements of SFAS No. 128, Columbia's EPS would be as
         follows:


<TABLE>
<CAPTION>
                                                                                 Three Months
                                                                                Ended March 31,
                                                                             -------------------
<S>                                                                            <C>        <C> 
  Diluted EPS Computation                                                      1998       1997
  ----------------------------------------------------------------------------------------------
  Net Income ($ millions)                                                      147.5      162.7
  ----------------------------------------------------------------------------------------------
  Denominator (thousands)
    Average common shares outstanding                                         55,511     55,332
    Dilutive potential common shares - options                                   181        126
  ----------------------------------------------------------------------------------------------
    Diluted Average Common Shares                                             55,692     55,458
  ----------------------------------------------------------------------------------------------
  Diluted Earnings Per Share of Common Stock ($)                                2.65       2.93
  ----------------------------------------------------------------------------------------------
</TABLE>




                                       8


<PAGE>   9



                         PART 1 - FINANCIAL INFORMATION
               ITEM I1 - MANAGEMENT'S DISCUSSION AND ANALYSIS OF
                  FINANCIAL CONDITION AND RESULTS OF OPERATIONS


                       OPERATING INCOME (LOSS) BY SEGMENT


<TABLE>
<CAPTION>
                                                                                   Three Months
                                                                                 Ended March 31,
                                                                            -----------------------
                                                                             1998             1997
                                                                            ------           ------
                                                                                  (millions)
<S>                                                                          <C>             <C>   
Transmission and Storage                                                     $119.7          $ 92.9

Distribution                                                                  120.1           140.6

Exploration and Production                                                     14.4            11.7

Marketing, Propane and Power Generation                                         0.1             9.9

Corporate                                                                      (0.1)            1.5
                                                                             ------          ------

   Total                                                                     $254.2          $256.6
                                                                             ======          =======
</TABLE>




                  DEGREE DAYS (DISTRIBUTION SERVICE TERRITORY)


<TABLE>
<CAPTION>
                                                                                    Three Months
                                                                                  Ended March 31,
                                                                              -----------------------
                                                                               1998              1997
                                                                              ------            -----
<S>                                                                            <C>             <C>  
Actual                                                                         2,319           2,693

Normal                                                                         2,947           2,947

% Colder (warmer) than normal                                                    (21)             (9)

% Colder (warmer) than prior period                                              (14)            (13)
</TABLE>




                                       9


<PAGE>   10

                         PART 1 - FINANCIAL INFORMATION
               ITEM I1 - MANAGEMENT'S DISCUSSION AND ANALYSIS OF
          FINANCIAL CONDITION AND RESULTS OF OPERATIONS (consolidated)
                        CONSOLIDATED RESULTS (continued)




Forward-Looking  Statements

The Management's Discussion and Analysis, including statements regarding market
risk sensitive instruments, contains "forward-looking statements," within the
meaning of Section 27A of the Securities Act of 1933 and Section 21E of the
Securities Exchange Act of 1934, as amended. Investors and prospective investors
should understand that several factors govern whether any forward-looking
statement contained herein will be or can be achieved. Any one of those factors
could cause actual results to differ materially from those projected herein.
These forward-looking statements include, but are not limited to, statements
concerning Columbia's plans, objectives, expected performance, expenditures and
recovery of expenditures through rates, stated on either a consolidated or
segment basis, and any and all underlying assumptions and other statements that
are other than statements of historical fact. From time to time, Columbia may
publish or otherwise make available forward-looking statements of this nature.
All such subsequent forward-looking statements, whether written or oral and
whether made by or on behalf of Columbia, are also expressly qualified by these
cautionary statements. All forward-looking statements are based on assumptions
that management believes to be reasonable; however, there can be no assurance
that actual results will not differ materially. Realization of Columbia's
objectives and expected performance is subject to a wide range of risks and can
be adversely affected by, among other things, competition, weather, regulatory
and legislative changes as well as changes in general economic, capital and
commodity market conditions many of which are beyond the control of Columbia. In
addition, the relative contributions to profitability by segment, and the
assumptions underlying the forward-looking statements relating thereto, may
change over time due to changes in the marketplace.

With respect to any references made to ratings assigned to Columbia's debt
securities, there can be no assurance that Columbia will be successful at
maintaining its credit quality or that such credit ratings will continue for any
given period of time or that they will not be revised downward or withdrawn
entirely by these rating agencies. Credit ratings reflect only the views of the
rating agencies, whose methodology and the significance of their ratings may be
obtained from them.

First Quarter Results

                                   Net Income

Columbia reported first quarter 1998 net income of $147.5 million, or earnings
of $2.66 per share, compared to $162.7 million, or $2.94 per share, during the
same period last year. This was a decrease of $15.2 million, or $0.28 per share,
due largely to the 21% warmer than normal weather experienced in Columbia's
service area in the first quarter of 1998. This year's January and February were
the warmest on record. Compared to normal, weather reduced earnings in the first
quarter of 1998 by $30.3 million, or $0.55 per share, and when compared to the
same period last year, which was also warmer than normal, the reduction was
$16.2 million or, $0.30 per share. Higher gross receipts and property taxes in
the distribution segment and start-up costs for the marketing company also
reduced current period results. Tempering these decreases was a $15 million
after-tax improvement for a reduction in the cost of certain postretirement
benefits reflecting a buyout of a portion of Columbia's liabilities with an
insurance carrier, an $8.5 million increase to net income from the sale of
certain storage base gas, as well as increased production and higher gas prices
for the exploration and production segment.

                                    Revenues

For the first quarter of 1998, net revenues of $622.5 million decreased $5.6
million when compared to the same period last year, reflecting the effect of
warmer weather on the distribution operations. This decrease was partially
offset by a $13.4 million increase from the sale of 5 billion cubic feet (Bcf)
of




                                       10

<PAGE>   11

                         PART 1 - FINANCIAL INFORMATION
               ITEM I1 - MANAGEMENT'S DISCUSSION AND ANALYSIS OF
          FINANCIAL CONDITION AND RESULTS OF OPERATIONS (consolidated)
                        CONSOLIDATED RESULTS (continued)



storage base gas, higher revenues from increased gas production and prices
together with higher net revenues for gas marketing operations due to additional
sales volumes. Sales for Columbia's gas marketing affiliate during the first
quarter of 1998 totaled 364.2 Bcf, an increase of 257.5 Bcf, or over 240%, from
the same period last year.

                                    Expenses

Operating expenses of $368.3 million for the first quarter of 1998 decreased
$3.2 million when compared to the same period last year largely reflecting a
reduction of $17.4 million in operation and maintenance expense. This decrease
was primarily the result of a $23.1 million reduction in the cost of certain
postretirement benefits, reflecting a buyout of a portion of Columbia's
liabilities with an insurance carrier. The transmission and storage segment's
operation and maintenance expense also decreased as a result of cost
conservation measures and efficiencies gained through recently implemented
restructuring activities. Tempering these improvements was approximately $13
million of start-up costs for the marketing operations. Depreciation and
depletion expense increased $2 million due to an increase in depletion expense
for the exploration and production segment resulting from the acquisition of
Alamco, Inc. and higher depletable revenues. Higher gross receipts and property
taxes in the distribution segment led to the $12.2 million increase in other
taxes.

                            Other Income (Deductions)

First quarter 1998 Other Income (Deductions), which includes other income and
interest expense, reduced income by $39.3 million compared to a decrease of $26
million in the same period last year. Other income of $2.3 million decreased $12
million when compared to the same period last year due largely to an $8.5
million gain recorded in 1997 for a payment received from the deactivation of a
storage field that allowed the owner of the coal reserves to mine the property.
Also reducing other income was reduced interest income on temporary cash
investments. Interest expense of $41.6 million increased $1.3 million from the
first quarter of 1997 primarily reflecting increased interest on short-term
borrowings. Both periods included $35.1 million of interest expense on long-term
debt.

                                  Income Taxes

Income tax expense remained relatively unchanged at $67.4 million despite lower
income; however, income tax expense was reduced $10 million in 1998 and $12.8
million in the first three months of 1997 for a reduction in the effective state
income tax rate due to the implementation of tax planning initiatives.

                         Liquidity and Capital Resources

A significant portion of Columbia's operations is subject to seasonal
fluctuations in cash flow. During the heating season, which is primarily from
November through March, cash receipts from sales and transportation services
typically exceed cash requirements. Conversely, during the remainder of the
year, cash on hand, together with external short-term and long-term financing,
as needed, is used to purchase gas to place in storage for heating season
deliveries, perform necessary maintenance of facilities, make capital
improvements in plant and expand service into new areas.

For the first three months of 1998, net cash from operations was $431.8 million,
a $77.7 million increase over the same period last year due largely to improved
cash from working capital despite reduced sales attributable to warmer first
quarter weather. Working capital changes improved cash from operations $196.3
million compared to $140 million in the same quarter last year. The working
capital improvement reflected changes in receivables and payables that included
an increase in the use of





                                       11

<PAGE>   12

                         PART 1 - FINANCIAL INFORMATION
               ITEM I1 - MANAGEMENT'S DISCUSSION AND ANALYSIS OF
          FINANCIAL CONDITION AND RESULTS OF OPERATIONS (consolidated)
                        CONSOLIDATED RESULTS (continued)



storage inventory and reduced purchases from producers. This improvement more
than offset a decrease in the overrecovery of gas costs by the distribution
subsidiaries. The decrease in the overrecovery position primarily reflects
higher gas prices in the current period compared to the same quarter in 1997.
The recovery of the commodity portion of the distribution subsidiaries' rates is
provided for under the current regulatory process.

Columbia satisfies its liquidity requirements through internally generated funds
and the use of two unsecured bank revolving credit facilities that total $1.35
billion (Credit Facilities). The Credit Facilities were established in March
1998, and replaced the $1 billion five-year revolving credit facility entered
into by Columbia in November 1995. The Credit Facilities also support Columbia's
commercial paper program.

Columbia's $1.35 billion Credit Facilities consist of a $900 million five-year
revolving credit facility and a $450 million 364-day revolving credit facility
with a one-year term loan option. The five-year facility provides for the
issuance of up to $300 million of letters of credit.

As of March 31, 1998, Columbia had approximately $42.8 million of letters of
credit outstanding under the Credit Facilities. Under Columbia's commercial
paper program, $22 million was outstanding at March 31, 1998.

Interest rates on borrowings under the Credit Facilities are based upon the
London Interbank Offered Rate, Certificate of Deposit rates or other short-term
interest rates. The interest rate margins and facility fees on the commitment
amount are based on Columbia's public debt ratings. In 1997, Fitch Investors
Service (Fitch), Moody's Investors Service, Inc. (Moody's) and Standard & Poor's
Ratings Group (S&P) upgraded Columbia's long-term debt rating to BBB+, Baa1 and
BBB+, respectively. Under the Credit Facilities, higher debt ratings result in
lower facility fees and interest rates on borrowings. Columbia's commercial
paper credit ratings are F-2 by Fitch, P-2 by Moody's and A-2 by S&P.

Columbia has an effective shelf registration statement on file with the U. S.
Securities and Exchange Commission for the issuance of up to $1 billion in
aggregate of debentures, common stock or preferred stock in one or more series.
In March 1996, Columbia issued 5,750,000 shares of common stock under the shelf
registration and used the proceeds to reduce borrowings incurred under the prior
credit facility and to retire $400 million of preferred stock issued in late
1995. No further issuances of the remaining $750 million available under the
shelf registration are scheduled at this time.

Management believes that its sources of funding are sufficient to meet
short-term and long-term liquidity needs not met by cash flows from operations.




                                       12


<PAGE>   13

                         PART 1 - FINANCIAL INFORMATION
                ITEM 2 - MANAGEMENT'S DISCUSSION AND ANALYSIS OF
           FINANCIAL CONDITION AND RESULTS OF OPERATIONS (CONTINUED)


                      TRANSMISSION AND STORAGE OPERATIONS
                      -----------------------------------

<TABLE>
<CAPTION>
                                                   Three Months
                                                  Ended March 31,
                                               -----------------------
                                                1998             1997
                                               ------           ------
<S>                                            <C>              <C>
OPERATING REVENUES
     Transportation revenues                   $180.1           $180.2
     Storage revenues                            46.6             43.5
     Other revenues                              20.6              9.7
                                               ------           ------
Total Operating Revenues                        247.3            233.4
                                               ------           ------

OPERATING EXPENSES
     Operation and maintenance                   85.9            100.1
     Depreciation                                26.0             26.3
     Other taxes                                 15.7             14.1
                                               ------           ------
Total Operating Expenses                        127.6            140.5
                                               ------           ------

OPERATING INCOME                               $119.7           $ 92.9
                                               ======           ======

THROUGHPUT (BCF)
Transportation
     Columbia Transmission
          Market area                           356.7            377.8
     Columbia Gulf
          Main-line                             130.7            151.0
          Short-haul                             62.2             62.0
          Intrasegment eliminations            (125.0)          (144.8)
                                               ------           ------
Total Throughput                                424.6            446.0
                                               ======           ======
</TABLE>



                                       13
<PAGE>   14


                         PART 1 - FINANCIAL INFORMATION
                    ITEM 2 - MANAGEMENT'S DISCUSSION AND ANALYSIS OF
          FINANCIAL CONDITION AND RESULTS OF OPERATIONS (continued)
                TRANSMISSION AND STORAGE OPERATIONS (continued)


Market Expansion Projects

The proposed Millennium Pipeline Project (Millennium Project), in which Columbia
Gas Transmission Corporation (Columbia Transmission) is participating and will
serve as developer and operator, will transport western gas supplies to
Northeast and Mid-Atlantic markets. The 442-mile pipeline will connect to
TransCanada Pipe Lines Ltd. at a new Lake Erie export point and transport up to
approximately 700 million cubic feet per day to Eastern markets. Eight shippers
have signed agreements for the available capacity. A filing with the Federal
Energy Regulatory Commission (FERC) requesting approval of the Millennium
Project, was made on December 22, 1997. This filing begins the extensive review
process, including opportunities for public review, communication and comment.
 The proposed in-service date is November 1999. Columbia Transmission will
continue its ongoing assessment of the project's schedule during the second
quarter of 1998. The current sponsors of the proposed Millennium Project are
Columbia Transmission, Westcoast Energy, Inc., TransCanada Pipe Lines Ltd., and
MCN Energy.

Regulatory Matters

                           Columbia Gulf's Rate Filing

Columbia Gulf Transmission Company (Columbia Gulf) filed a general rate case in
October 1996, which became effective on May 1, 1997, subject to refund. Active
parties in the proceeding have unanimously agreed to the terms of settlement
that was filed with the FERC on March 3, 1998. A letter approving the
settlement, without modification or condition, was issued by the FERC on April
29, 1998 and will become final following a 30-day period for the filing of
requests for rehearing. The approval of the settlement will not have a material
impact on Columbia's consolidated financial statements.

               Columbia Transmission's Environmental Cost Recovery

Columbia Transmission's 1997 rate case settlement excluded the issue of
environmental cost recovery and provided for a hearing to address these issues.
The procedural schedule established by the presiding Administrative Law Judge
provided for a hearing to commence in the fall of 1998. However, at the request
of Columbia Transmission and other active parties, the schedule was suspended on
May 5, 1998 in order to afford the parties to pursue settlement discussions.
These discussions are at an early stage and it is not possible to predict
whether or not they will be successful. It remains management's view that the
ultimate outcome of this proceeding will not have a material impact on
Columbia's consolidated financial statements.

                Challenge to Columbia Transmission's Rate Design

Pursuant to a provision of Columbia Transmission's 1997 rate settlement, the New
York Public Service Commission (NYPSC) had the right to initiate a hearing
challenging the appropriateness of the Straight Fixed Variable (SFV) rate design
for Columbia Transmission. In a decision rendered on April 23, 1998, the
presiding Administrative Law Judge dismissed the issue through grant of a motion
filed jointly by several interested parties. It was found that the NYPSC failed
to demonstrate that continued use of the SFV rate design on Columbia
Transmission's system would be unjust or unreasonable.

Sale of Certain Facilities

As previously reported in Columbia's 1997 Annual Report on Form 10-K, Columbia
Transmission has agreed to sell certain natural gas pipeline facilities that
consist of approximately 341 miles of pipeline, together with property and
associated facilities, located in New York and Pennsylvania. Columbia
Transmission will seek approval from the FERC to abandon the facilities in the
second quarter of 1998. The sale of these assets will not have a material impact
on Columbia's financial results.

Also as previously reported in Columbia's 1997 Annual Report on Form 10-K,
Columbia Transmission is in the process of selling its gathering facilities. As
part of this process, Columbia Transmission's anticipated sale of 750 miles of
gathering facilities by the second quarter of 1998 to Columbia Natural
Resources Inc. may be delayed due to a dispute with a gas distribution company.
The delay in the sale of these assets is not expected to have a material impact
on Columbia's financial results.

Bankruptcy-related Producer Claim

On April 27, 1998, the Claims Mediator issued a recommended finding disallowing
the claim of KV Oil & Gas (KV). The Claims Mediator concluded that Columbia
Transmission was not obligated to purchase gas under the





                                       14


<PAGE>   15
                         PART 1 - FINANCIAL INFORMATION
                    ITEM 2 - MANAGEMENT'S DISCUSSION AND ANALYSIS OF
          FINANCIAL CONDITION AND RESULTS OF OPERATIONS (continued)
                TRANSMISSION AND STORAGE OPERATIONS (continued)



KV contracts due to permanent release and therefore, the KV claim was not valid.
Columbia Transmission will file a motion to have the claim disallowed by the
Bankruptcy Court. Only two producer claims remain to be resolved by the
Bankruptcy Court.

Environmental Matters

Columbia's transmission subsidiaries have implemented programs to continually
review compliance with existing environmental standards. In addition, Columbia
Transmission continues to review past operational activities and to formulate
remediation programs where necessary. Columbia Transmission is currently
conducting assessment, characterization and remediation activities at specific
sites under a 1995 Environmental Protection Agency (EPA) Administrative Order by
Consent (AOC).

Consistent with Statement of Financial Accounting Standards No. 71, "Accounting
for the Effects of Certain Types of Regulation," a regulatory asset has been
recorded to the extent environmental expenditures are expected to be recovered
through rates. As noted above, Columbia Transmission's 1997 rate settlement
excluded the issue of environmental cost recovery and ordered a hearing to
address this issue. Columbia Transmission continues to pursue recovery of
environmental expenditures from its insurance carriers and has met with some
success; however at this time, management is unable to determine the total
amount or final disposition of any such recovery. Management does not believe
that Columbia Transmission's environmental expenditures will have a material
adverse effect on its operations, liquidity or financial position, based on
known facts and existing laws and regulations and the long period over which
expenditures will be made.

Throughput

Columbia Transmission's throughput consists of transportation and storage
services for local distribution companies and other customers within its market
area which covers fifteen northeastern, midatlantic, midwestern and southern
states and the District of Columbia. Throughput for Columbia Gulf reflects
mainline transportation services from Rayne, Louisiana, to West Virginia and
short-haul transportation services from the Gulf of Mexico to Rayne, Louisiana.

Total throughput for the transmission and storage segment totaled 424.6 Bcf for
the first quarter of 1998, a decrease of 21.4 Bcf from the same period last
year. This decline was primarily due to the warmer weather experienced during
the first quarter of 1998. Tempering the decline were new contracts resulting
from Columbia Transmission's market expansion project. Under FERC Order No. 636,
a significant portion of the transmission and storage segment's fixed costs are
being recovered through a monthly demand charge. As a result, variations in
throughput do not have a significant impact on income.

Operating Revenues

Total operating revenues of $247.3 million for the first quarter of 1998
increased $13.9 million over the same period in 1997. After adjusting for the
recovery of upstream transportation costs and certain other revenues that are
fully offset in operating expense, current operating revenues increased $16.1
million. This increase was largely due to the sale of approximately 5 Bcf of
base gas volumes that were part of Columbia Transmission's overall rate case
settlement in 1997. Increased revenues from transportation and storage services,
primarily related to Columbia Transmission's market expansion contracts, also
contributed to the improvement. Tempering these improvements were reduced
revenues resulting from the sale of certain gathering facilities in 1997.

Operating Income

First quarter 1998 total operating income for the transportation and storage
segment was $119.7 million, an increase of $26.8 million over the first three
months of 1997. This improvement reflected $13.9 million




                                       15


<PAGE>   16
                         PART 1 - FINANCIAL INFORMATION
                    ITEM 2 - MANAGEMENT'S DISCUSSION AND ANALYSIS OF
          FINANCIAL CONDITION AND RESULTS OF OPERATIONS (continued)
                TRANSMISSION AND STORAGE OPERATIONS (continued)



higher operating revenues, as discussed previously, and $12.9 million lower
operating expenses. Operation and maintenance expenses declined $14.2 million
primarily reflecting savings achieved through the implementation of
restructuring initiatives and a $4.5 million reduction in the cost of certain
postretirement benefits, as discussed previously. In 1997, franchise taxes were
$1.2 million lower due to the prior year adjustment on the consolidated tax
return filing.







                                       16

<PAGE>   17
                         PART 1 - FINANCIAL INFORMATION
                ITEM 2 - MANAGEMENT'S DISCUSSION AND ANALYSIS OF
           FINANCIAL CONDITION AND RESULTS OF OPERATIONS (continued)
                TRANSMISSION AND STORAGE OPERATIONS (continued)


                             DISTRIBUTION OPERATIONS
                             -----------------------
<TABLE>
<CAPTION>
                                                                       Three Months
                                                                      Ended March 31,
                                                                  -----------------------
                                                                   1998            1997
                                                                  ------         --------
                                                                        (millions)
<S>                                                               <C>            <C>
NET REVENUES
     Sales revenues                                               $744.0         $1,025.2
     Less: Cost of gas sold                                        481.5            719.1
                                                                  ------         --------
     Net Sales Revenues                                            262.5            306.1
                                                                  ------         --------

     Transportation revenues                                        57.7             42.1
     Less: Associated gas costs                                      5.6              2.9
                                                                  ------         --------
     Net Transportation Revenues                                    52.1             39.2
                                                                  ------         --------

Net Revenues                                                       314.6            345.3
                                                                  ------         --------

OPERATING EXPENSES
     Operation and maintenance                                      91.9            110.2
     Depreciation                                                   33.8             35.6
     Other taxes                                                    68.8             58.9
                                                                  ------         --------
Total Operating Expenses                                           194.5            204.7
                                                                  ------         --------

OPERATING INCOME                                                  $120.1         $  140.6
                                                                  ======         ========

THROUGHPUT (BCF)
     Sales
          Residential                                               72.0             88.4
          Commercial                                                26.6             34.1
          Industrial and other                                       1.6              0.3
                                                                  ------         --------
     Total Sales                                                   100.2            122.8
     Transportation                                                 84.1             72.0
                                                                  ------         --------
Total Throughput                                                   184.3            194.8
Off-System Sales                                                    29.0             31.3
                                                                  ------         --------
Total Sold or Transported                                          213.3            226.1

SOURCES OF GAS FOR THROUGHPUT (BCF)
     Sources of Gas Sold
          Spot market*                                              61.4             61.6
          Producers                                                  5.7             11.5
          Storage withdrawals (injections)                          63.7             82.7
          Other                                                     (1.6)            (1.7)
                                                                  ------         --------
     Total Sources of Gas Sold                                     129.2            154.1
          Transportation received for delivery to customers         84.1             72.0
                                                                  ------         --------
Total Sources                                                      213.3            226.1
                                                                  ======         ========
</TABLE>


* Purchase contracts of less than one year.



                                       17
<PAGE>   18
                         PART 1 - FINANCIAL INFORMATION
                    ITEM 2 - MANAGEMENT'S DISCUSSION AND ANALYSIS OF
          FINANCIAL CONDITION AND RESULTS OF OPERATIONS (continued)



                      DISTRIBUTIONS OPERATIONS (continued)


Market Conditions

Weather in the areas served by Columbia's distribution subsidiaries
(Distribution) in January and February 1998 was the warmest on record. For the
first quarter of 1998, the weather was 21% warmer than normal and 14% warmer
than the first quarter of 1997. As a result, Distribution's weather-sensitive
deliveries declined 16 Bcf when compared to the same period last year.

Regulatory Matters

On March 31, 1998, Columbia Gas of Ohio, Inc. (Columbia of Ohio) filed a request
with the Public Utilities Commission of Ohio (PUCO) seeking approval to extend
its Customer CHOICE(R) program to all of its nearly 1.3 million Ohio customers.
PUCO approval of the expansion is expected in mid-to-late spring, with
implementation by late summer 1998.

In February 1998, Columbia Gas of Virginia, Inc. (Columbia of Virginia) received
the Virginia State Corporation Commission (VSCC) report in its rate case filed
in May 1997. Columbia of Virginia requested an annual increase of approximately
$8.5 million to recover normal increases in the cost of service; however, the
VSCC staff recommended no increase in annual revenue for Columbia of Virginia in
its report. On March 5, 1998, Columbia of Virginia filed rebuttal testimony,
countering the staff's recommendation. The VSCC staff filed supplemental
testimony, updating its recommended annual increase to $1.1 million. The hearing
concluded April 2, 1998 and post-hearing briefs will be submitted approximately
60 days thereafter.

On March 9, 1998, Columbia of Virginia filed a notice with the VSCC stating the
company's intention to file a new general rate case in May 1998.

On April 24, 1998, Columbia Gas of Pennsylvania, Inc. (Columbia of Pennsylvania)
filed for permission from the Pennsylvania Public Utility Commission (PPUC) to
expand its pilot Customer CHOICE(R) program into five new counties in the second
quarter of 1998. Programs are already in operation in Allegheny and Washington
counties and the proposed extension would mean that approximately two-thirds of
Columbia of Pennsylvania's customer base of 382,000 would be eligible to
participate in the Customer CHOICE(R) program.

On February 25, 1998, the Maryland Public Service Commission (MPSC) approved the
agreement reached by Columbia of Maryland, Inc. with the MPSC staff and the
Maryland People's Counsel. The agreement, as reported in Columbia's 1997 Annual
Report on Form 10-K, provides for an annual revenue increase of $200,000. The
increased rates went into effect with customer bills processed after March 15,
1998.

Throughput

For the quarter ended March 31, 1998, throughput of 184.3 Bcf was 10.5 Bcf lower
than the same period last year as the impact of the unusually warm weather on
tariff sales was only partially offset by customer growth, an increase in
transportation volumes and the return to full production of a manufacturing
facility which had been idled by a labor strike during the first quarter of
1997.

Net Revenues

Net revenues for the quarter ended March 31, 1998, were $314.6 million, down
$30.7 million from the first quarter of 1997. This decrease primarily reflects
the adverse impact of warm weather, which was only partially offset by the
beneficial effect of a Columbia of Ohio regulatory settlement.




                                       18


<PAGE>   19
                         PART 1 - FINANCIAL INFORMATION
                    ITEM 2 - MANAGEMENT'S DISCUSSION AND ANALYSIS OF
          FINANCIAL CONDITION AND RESULTS OF OPERATIONS (continued)



                      DISTRIBUTION OPERATIONS (continued)




Operating Income

Operating Income for the first quarter of 1998 of $120.1 million was down $20.5
million from the same period last year due to the decline in net revenues
tempered by a $10.2 million decrease in operating expenses. Operation and
maintenance expense was down $18.3 million primarily reflecting a $15 million
adjustment to benefits expense to reflect a reduction in certain postemployment
benefit costs. Other taxes were up $9.9 million primarily due to higher gross
receipts and property taxes. The recognition of gross receipts taxes generally
lags several months from the recording of the associated revenues.




                                       19


<PAGE>   20
                         PART 1 - FINANCIAL INFORMATION
                ITEM 2 - MANAGEMENT'S DISCUSSION AND ANALYSIS OF
           FINANCIAL CONDITION AND RESULTS OF OPERATIONS (continued)


                     EXPLORATION AND PRODUCTION OPERATIONS
                     -------------------------------------

<TABLE>
<CAPTION>
                                            Three Months
                                           Ended March 31,
                                         ------------------
                                          1998        1997
                                         ------      ------
                                             (millions)
<S>                                       <C>       <C>   
OPERATING REVENUES
     Gas                                  $33.6     $ 27.9
     Other                                  3.8        1.1
                                          -----     ------
Total Operating Revenues                   37.4       29.0
                                          -----     ------

OPERATING EXPENSES
     Operation and maintenance             10.4        8.7
     Depreciation and depletion            10.2        6.8
     Other taxes                            2.4        1.8
                                          -----     ------
Total Operating Expenses                   23.0       17.3
                                          -----     ------
OPERATING INCOME                          $14.4     $ 11.7
                                          =====     ======


GAS PRODUCTION STATISTICS
Production (Bcf)                            9.9        8.3

Average Price (per Mcf)                  $ 3.38     $ 2.76

OIL AND LIQUIDS PRODUCTION STATISTICS
Production (000Bbls)                         58         52

Average Price (per Bbl)                  $14.31     $21.07
</TABLE>





                                       20
<PAGE>   21

                         PART 1 - FINANCIAL INFORMATION
                    ITEM 2 - MANAGEMENT'S DISCUSSION AND ANALYSIS OF
          FINANCIAL CONDITION AND RESULTS OF OPERATIONS (continued)
                     EXPLORATION AND PRODUCTION (continued)




Drilling Activity

Through the first quarter of 1998, Columbia Natural Resources, Inc. (Columbia
Resources) participated in 16 gross wells of which 75% were successful. These
wells added 2.5 net billion cubic feet equivalent (Bcfe) to reserves, an
increase of 1.1 net Bcfe over the first quarter of 1997. Drilling activity is up
45 percent from 1997 primarily due to the acquisition of Alamco, Inc. (Alamco)
and significant natural gas discoveries in New York.

Volumes

Gas production during the first quarter of 1998 increased nearly 20% over the
prior period to 9.9 Bcf as the result of the Alamco acquisition, successful
exploratory drilling in New York and Columbia Resources' aggressive 1997
drilling program. Oil and liquids production of 57,900 barrels decreased nearly
6,000 barrels from the first quarter of 1997.

Revenues

Revenues of $37.4 million for the first quarter of 1998 increased $8.4 million
from the same period last year. Gas revenues increased $5.7 million due to the
increase in volumes and higher gas prices. For the quarter ended March 31, 1998,
Columbia Resources' average gas sales price was $3.38 per Mcf compared to $2.76
per Mcf in the first quarter of 1997. The stronger natural gas prices reflected
the benefit of hedging activity last fall when prices were near their peak. In
addition, third party gathering revenues increased more than $2 million. As
previously reported in Columbia's 1997 Annual Report on Form 10-K, certain
gathering facilities were transferred from Columbia Transmission to Columbia
Resources in the third quarter of 1997. In the first quarter of 1997, $4.1
million of revenues were recorded to reflect a payment made by a cogeneration
partnership to allow it to terminate its gas purchase contract with Columbia
Resources.

Operating Income

Operating income for the current quarter increased $2.7 million to $14.4 million
from 1997 first quarter results. The revenue improvement was largely offset by
higher operation and maintenance expense due to the additional costs associated
with the acquisition of Alamco and the transfer of the gathering facilities as
well as an increase in depletion expense due to higher prices.






                                       21



<PAGE>   22
                         PART 1 - FINANCIAL INFORMATION
                ITEM 2 - MANAGEMENT'S DISCUSSION AND ANALYSIS OF
           FINANCIAL CONDITION AND RESULTS OF OPERATIONS (CONTINUED)


               MARKETING, PROPANE AND POWER GENERATION OPERATIONS
               --------------------------------------------------

<TABLE>
<CAPTION>
                                                        Three Months
                                                       Ended March 31,
                                                    --------------------
                                                     1998          1997
                                                    ------        ------
                                                         (millions)
<S>                                                 <C>           <C>
NET REVENUES
     Gas marketing revenues                         $859.1        $305.7
     Less: Products purchased                        847.8         300.4
                                                    ------        ------
     Net Gas Marketing Revenues                       11.3           5.3
                                                    ------        ------

     Propane revenues                                 26.3          28.5
     Less: Products purchased                         12.9          16.2
                                                    ------        ------
     Net Propane Revenues                             13.4          12.3
                                                    ------        ------

     Other Revenues                                    1.5           5.9
                                                    ------        ------

Net Revenues                                          26.2          23.5
                                                    ------        ------

OPERATING EXPENSES
     Operation and maintenance                        23.3          11.9
     Depreciation                                      1.7           0.9
     Other taxes                                       1.1           0.8
                                                    ------        ------
Total Operating Expenses                              26.1          13.6
                                                    ------        ------

OPERATING INCOME                                    $  0.1        $  9.9
                                                    ======        ======

PROPANE SALES (MILLIONS OF GALLONS)
     Retail                                           22.8          21.1
     Wholesale and Other                               2.0           3.7
                                                    ------        ------
Total Propane Sales                                   24.8          24.8
                                                    ======        ======

MARKETING SALES
     Gas Sales (billion cubic feet)                  364.2         106.7
     Power Sales (thousand megawatt hours)           304.8          --
</TABLE>



                                       22
<PAGE>   23


                         PART 1 - FINANCIAL INFORMATION
                ITEM 2 - MANAGEMENT'S DISCUSSION AND ANALYSIS OF
            FINANCIAL CONDITION AND RESULTS OF OPERATIONS (continued)

         MARKETING, PROPANE AND POWER GENERATION OPERATIONS (continued)

Columbia Joins Power Pool

In the first quarter of 1998, Columbia Energy Services Corporation (Columbia
Energy Services), through a subsidiary, joined the Pennsylvania-New
Jersey-Maryland (PJM) electric power pool that covers much of the heavily
populated mid-Atlantic region of the U.S. Columbia Energy Services began trading
electric power in late-1997. Membership in the PJM gives Columbia Energy
Services access to the region's high voltage transmission lines to send power
through the pool or to deliver it to customers within the region and will serve
as an integral part of Columbia Energy Services' retail customer choice program.

Propane Acquisition

In May 1998, Columbia Propane Corporation announced it had purchased the propane
assets of the Frederick Division of Washington Gas Light Company. This division
sells approximately 1.4 million gallons of propane annually to 2,900 customers
in the Frederick, Maryland area.

Net Revenues

Net revenues of $26.2 million for the first quarter of 1998 increased $2.7
million from the same period last year. Sales volumes for Columbia Energy
Services were over 240% more than last year's level, reflecting the significant
growth of Columbia Energy Services, including the effect of the PennUnion Energy
Services L.L.C. acquisition and the agreement with Kerr-McGee Corporation to
purchase and market its off-shore natural gas production. However, much of the
growth came from increased lower-margin wholesale sales which reduced Columbia
Energy Services' average margins for the current quarter that partially offset
the impact of higher sales volumes. In total, gas marketing net revenues
increased $6 million. Propane net revenues for the first quarter of 1998 were up
$1.1 million due to 5% higher margins, reflecting an increase in sales to retail
customers. Propane volumes remained unchanged as the addition of four new
districts acquired with the purchase of both Supertane Gas Corporation's assets
and certain assets of Central Jersey Propane, Inc., known as Ace Gas, offset the
decline due to the warmer weather experienced in the first quarter of 1998. In
the first quarter of 1997, Columbia Electric recorded a $3.2 million improvement
from the assumption of the Binghamton Partnership fuel transportation contract.

Operating Income

Operating income of $100,000 decreased $9.8 million from the first quarter of
1997. The increase in net revenues was more than offset by higher operating
costs associated with growing the gas marketing operations and building its
infrastructure. These costs include, among other things, implementing
operational improvements and increasing its staffing levels.



                         PART 1 - FINANCIAL INFORMATION
       ITEM 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

There have not been any material changes regarding quantitative and qualitative
disclosures about market risk from the information reported in Columbia's 1997
Annual Report on Form 10-K.




                                       23


<PAGE>   24


                           PART II - OTHER INFORMATION




Item l.   Legal Proceedings

          No new reportable matters have arisen and there have been no
          material developments in any legal proceedings reported in
          Columbia's Annual Report on Form 10-K for the year ended 
          December 31, 1997.


Item 2.    Changes in Securities and Use of Proceeds

              None


Item 3.   Defaults Upon Senior Securities

              None


Item 4.   Submission of Matters to a Vote of Security Holders

              None


Item 5.   Other Information

               None


Item 6.   Exhibits and Reports on Form 8-K

               Exhibit
               Number
               -------
                12       Statements of Ratio of Earnings to Fixed Charges and 
                         Preferred Stock Dividends

                27       Financial Data Schedule


               The following reports on Form 8-K were filed during the first
               quarter of 1998.

<TABLE>
<CAPTION>
                                       Financial
                        Item          Statements
                     Reported          Included       Date of Event          Date Filed
                     --------         ----------     ----------------      --------------
<S>                       <C>           <C>            <C>                  <C>
                          5              Yes *          April 20, 1998        April 22, 1998
                          5               No          January 16, 1998      January 20, 1998
                          5              Yes **       January 23, 1998      January 26, 1998
</TABLE>


          *    Summary of Financial and Operational data for three months ended
               March 31, 1998.

          **   Summary of Financial and Operational data for twelve and three
               months ended December 31, 1997.



                                       24

<PAGE>   25

                                    SIGNATURE



     Pursuant to the requirements of the Securities Exchange Act of 1934, the
     Registrant has duly caused this report to be signed on its behalf by the
     undersigned thereunto duly authorized.




                                                Columbia Energy Group
                                             ---------------------------
                                                    (Registrant)









Date: May 13, 1998                        By:  /s/ Jeffrey W. Grossman
                                             ---------------------------
                                                   Jeffrey W. Grossman
                                              Vice President and Controller
                                              (Principal Accounting Officer
                                               and Duly Authorized Officer)




                                       25