<PAGE>

===============================================================================

                                 UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                ---------------

                                   FORM 10-Q
(Mark One)
[X]   QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d)
                  OF THE SECURITIES EXCHANGE ACT OF 1934

             FOR THE QUARTERLY PERIOD ENDED SEPTEMBER 30, 2001

                                       OR

[   ]   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 1-2745

                                ---------------

                          SOUTHERN NATURAL GAS COMPANY
             (Exact Name of Registrant as Specified in its Charter)

<Table>
<S>                                                 <C>
                     DELAWARE                                           63-0196650
          (State or Other Jurisdiction of                            (I.R.S. Employer
          Incorporation or Organization)                            Identification No.)
</Table>

<Table>
<S>                                                 <C>
                 EL PASO BUILDING
               1001 LOUISIANA STREET                                       77002
                  HOUSTON, TEXAS                                        (Zip Code)
     (Address of Principal Executive Offices)
</Table>

       Registrant's Telephone Number, Including Area Code: (713) 420-2600

     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, par value $3.75 per share. Shares outstanding on November 6,
2001: 1,000

     SOUTHERN NATURAL GAS COMPANY MEETS THE CONDITIONS OF GENERAL INSTRUCTION
H(1)(a) AND (b) OF FORM 10-Q AND IS THEREFORE FILING THIS REPORT WITH A REDUCED
DISCLOSURE FORMAT AS PERMITTED BY SUCH INSTRUCTION.

===============================================================================
<PAGE>

                        PART I -- FINANCIAL INFORMATION

ITEM 1. FINANCIAL STATEMENTS

                          SOUTHERN NATURAL GAS COMPANY

                  CONDENSED CONSOLIDATED STATEMENTS OF INCOME
                                 (IN MILLIONS)
                                  (UNAUDITED)

<Table>
<Caption>
                                                           QUARTER ENDED       NINE MONTHS ENDED
                                                           SEPTEMBER 30,         SEPTEMBER 30,
                                                           --------------      ------------------
                                                           2001      2000       2001        2000
                                                           ----      ----      ------      ------
<S>                                                        <C>       <C>       <C>         <C>
Operating revenues.......................................  $89       $96        $294        $301
                                                           ---       ---        ----        ----
Operating expenses
  Operation and maintenance..............................   38        45         125         126
  Depreciation, depletion and amortization...............   10        10          31          23
  Taxes, other than income taxes.........................    4         5          14          16
                                                           ---       ---        ----        ----
                                                            52        60         170         165
                                                           ---       ---        ----        ----
Operating income.........................................   37        36         124         136
                                                           ---       ---        ----        ----
Other income
  Earnings from unconsolidated affiliates................    4         3          11          12
  Other, net.............................................    2        --           7          (2)
                                                           ---       ---        ----        ----
                                                             6         3          18          10
                                                           ---       ---        ----        ----
Income before interest, income taxes and other charges...   43        39         142         146
                                                           ---       ---        ----        ----
Non-affiliated interest and debt expense.................   13        10          36          29
Affiliated interest income, net..........................   (4)       (5)        (14)         (4)
Income taxes.............................................   14        13          47          47
                                                           ---       ---        ----        ----
                                                            23        18          69          72
                                                           ---       ---        ----        ----
Income before extraordinary items........................   20        21          73          74
Extraordinary items, net of income taxes.................   --        --          --          12
                                                           ---       ---        ----        ----
Net income...............................................  $20       $21        $ 73        $ 86
                                                           ===       ===        ====        ====
</Table>

                            See accompanying notes.

                                        1
<PAGE>

                          SOUTHERN NATURAL GAS COMPANY

                     CONDENSED CONSOLIDATED BALANCE SHEETS
                      (IN MILLIONS, EXCEPT SHARE AMOUNTS)
                                  (UNAUDITED)

<Table>
<Caption>
                                                              SEPTEMBER 30,   DECEMBER 31,
                                                                  2001            2000
                                                              -------------   ------------
<S>                                                           <C>             <C>
                                          ASSETS

Current assets
  Cash and cash equivalents.................................     $   --          $   --
  Accounts and notes receivable, net
    Customer................................................         51              74
    Affiliates..............................................        434             214
    Other...................................................          3               9
  Materials and supplies....................................         14              15
  Regulatory assets.........................................         29              27
  Other.....................................................          1              --
                                                                 ------          ------
         Total current assets...............................        532             339
                                                                 ------          ------
Property, plant and equipment, at cost......................      2,640           2,529
Less accumulated depreciation, depletion and amortization...      1,343           1,313
                                                                 ------          ------
         Total property, plant and equipment, net...........      1,297           1,216
                                                                 ------          ------
Other assets
  Investments in unconsolidated affiliates..................        115             105
  Other.....................................................         27              12
                                                                 ------          ------
                                                                    142             117
                                                                 ------          ------
         Total assets.......................................     $1,971          $1,672
                                                                 ======          ======

                           LIABILITIES AND STOCKHOLDER'S EQUITY

Current liabilities
  Accounts payable
    Trade...................................................     $   41          $   37
    Affiliates..............................................         61              11
    Other...................................................          2               2
  Current maturities of long-term debt......................        200             100
  Taxes payable.............................................         58              91
  Accrued interest..........................................         23              24
  Other.....................................................          2               4
                                                                 ------          ------
         Total current liabilities..........................        387             269
                                                                 ------          ------
Long-term debt, less current maturities.....................        498             399
                                                                 ------          ------
Deferred income taxes.......................................        147             120
                                                                 ------          ------
Other.......................................................         48              67
                                                                 ------          ------
Commitments and contingencies
Stockholder's equity
  Common stock, par value $3.75 per share; authorized and
    issued 1,000 shares.....................................         --              --
  Additional paid-in capital................................        103             102
  Retained earnings.........................................        788             715
                                                                 ------          ------
         Total stockholder's equity.........................        891             817
                                                                 ------          ------
         Total liabilities and stockholder's equity.........     $1,971          $1,672
                                                                 ======          ======
</Table>

                            See accompanying notes.

                                        2
<PAGE>

                          SOUTHERN NATURAL GAS COMPANY

                CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS
                                 (IN MILLIONS)
                                  (UNAUDITED)

<Table>
<Caption>
                                                              NINE MONTHS ENDED
                                                                SEPTEMBER 30,
                                                              ------------------
                                                               2001        2000
                                                              ------      ------
<S>                                                           <C>         <C>
Cash flows from operating activities
  Net income................................................  $  73       $  86
  Adjustments to reconcile net income to net cash from
     operating activities
     Depreciation, depletion and amortization...............     31          23
     Extraordinary items....................................     --         (21)
     Deferred income tax expense (benefit)..................     28         (10)
     Net gain on the sale of assets.........................     (1)         --
     Undistributed earnings of unconsolidated affiliates....    (11)        (11)
  Working capital changes, net of non-cash transactions.....     28          74
  Non-working capital changes and other.....................    (39)         27
                                                              -----       -----
          Net cash provided by operating activities.........    109         168
                                                              -----       -----
Cash flows from investing activities
  Additions to property, plant and equipment................    (93)        (58)
  Proceeds from the sale of investments.....................     --         159
  Net change in other affiliated advances receivable........   (225)       (274)
  Net proceeds from the sale of assets......................      9          74
                                                              -----       -----
          Net cash used in investing activities.............   (309)        (99)
                                                              -----       -----
Cash flows from financing activities
  Payments to retire long-term debt.........................   (100)         --
  Proceeds from the issuance of long-term debt..............    300          --
  Net change in other affiliated advances payable...........     --         (70)
                                                              -----       -----
          Net cash provided by (used in) financing
           activities.......................................    200         (70)
                                                              -----       -----
Decrease in cash and cash equivalents.......................     --          (1)
Cash and cash equivalents
  Beginning of period.......................................     --           1
                                                              -----       -----
  End of period.............................................  $  --       $  --
                                                              =====       =====
</Table>

                            See accompanying notes.

                                        3
<PAGE>

                          SOUTHERN NATURAL GAS COMPANY

              NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS
                                  (UNAUDITED)

1. BASIS OF PRESENTATION

     Our 2000 Annual Report on Form 10-K includes a summary of our significant
accounting policies and other disclosures. You should read it in conjunction
with this Quarterly Report on Form 10-Q. The financial statements as of
September 30, 2001, and for the quarters and nine months ended September 30,
2001 and 2000, are unaudited. The balance sheet as of December 31, 2000, is
derived from the audited balance sheet included in our Annual Report on Form
10-K. These financial statements have been prepared pursuant to the rules and
regulations of the U.S. Securities and Exchange Commission and do not include
all disclosures required by accounting principles generally accepted in the
United States. In our opinion, we have made all adjustments, all of which are of
a normal, recurring nature, to fairly present our interim period results.
Information for interim periods may not necessarily indicate the results of
operations for the entire year due to the seasonal nature of our business. The
prior period information also includes reclassifications which were made to
conform to the current period presentation. These reclassifications have no
effect on our reported net income or stockholder's equity.

2. EXTRAORDINARY ITEMS

     During the first quarter of 2000, we sold Sea Robin Pipeline Company to
comply with a Federal Trade Commission (FTC) order related to our former parent
company's merger with El Paso Corporation. Net proceeds from this sale were $71
million, and we recognized an extraordinary gain of $12 million, net of income
taxes of $9 million. In May 2000, we disposed of our one-third interest in
Destin Pipeline Company to comply with the same FTC order. Net proceeds from
this sale were $159 million, and no material gain or loss was recognized on the
transaction.

3. DEBT AND OTHER CREDIT FACILITIES

     In February 2001, we issued $300 million aggregate principal amount 7.35%
notes due 2031. Proceeds of approximately $297 million, net of issuance costs,
were used to pay off $100 million of our 8.875% notes due 2001 and for operating
purposes.

4. COMMITMENTS AND CONTINGENCIES

  Legal Proceedings

     In 1997, we and a number of our affiliates were named defendants in actions
brought by Jack Grynberg on behalf of the U.S. Government under the False Claims
Act. Generally, these complaints allege an industry-wide conspiracy to under
report the heating value as well as the volumes of the natural gas produced from
federal and Native American lands, which deprived the U.S. Government of
royalties. These matters have been consolidated for pretrial purposes (In re:
Natural Gas Royalties Qui Tam Litigation, U.S. District Court for the District
of Wyoming). In May 2001, the court denied the defendants' motions to dismiss.

     We and a number of our affiliates were named defendants in Quinque
Operating Company, et al v. Gas Pipelines and Their Predecessors, et al, filed
in 1999 in the District Court of Stevens County, Kansas. This class action
complaint alleges that the defendants mismeasured natural gas volumes and
heating content of natural gas on non-federal and non-Native American lands. The
Quinque complaint was transferred to the same court handling the Grynberg
complaint and has now been sent back to Kansas State Court for further
proceedings. A motion to dismiss this case is pending.

     We are also a named defendant in numerous lawsuits and a named party in
numerous governmental proceedings arising in the ordinary course of our
business.

                                        4
<PAGE>

     While the outcome of the matters discussed above cannot be predicted with
certainty, based on information known to date, we do not expect the ultimate
resolution of these matters to have a material adverse effect on our ongoing
financial position, operating results or cash flows.

  Environmental

     We are subject to extensive federal, state and local laws and regulations
governing environmental quality and pollution control. These laws and
regulations require us to remove or remedy the effect on the environment of the
disposal or release of specified substances at current and former operating
sites. As of September 30, 2001, we had a reserve of approximately $12 million
for expected remediation costs. In addition, we expect to make capital
expenditures for environmental matters of approximately $7 million in the
aggregate for the years 2001 through 2006. These expenditures primarily relate
to compliance with clean air regulations.

     We have been designated and have received notice that we could be
designated, or have been asked for information to determine whether we could be
designated, as a Potentially Responsible Party (PRP) with respect to one active
site under the Comprehensive Environmental Response, Compensation and Liability
Act (CERCLA) or state equivalents. We are currently evaluating our potential
share, if any of the remediation costs.

     It is possible that new information or future developments could require us
to reassess our potential exposure related to environmental matters. We may
incur significant costs and liabilities in order to comply with existing
environmental laws and regulations. It is also possible that other developments,
such as increasingly strict environmental laws and regulations and claims for
damages to property, employees, other persons and the environment resulting from
our current or past operations, could result in substantial costs and
liabilities in the future. As this information becomes available, or other
relevant developments occur, we will adjust our accrual amounts accordingly.
While there are still uncertainties relating to the ultimate costs we may incur,
based upon our evaluation and experience to date, we believe the recorded
reserves are adequate.

  Rates and Regulatory Matters

     In March 2000, the Federal Energy Regulatory Commission (FERC) issued an
order which authorized the recommissioning of our Elba Island liquefied natural
gas (LNG) receiving terminal near Savannah, Georgia. In July 2001, FERC issued a
final order approving a modification of the sendout facilities at the terminal
subject to certain conditions. In October 2001, we received an initial cargo of
LNG, in order to test the facilities. In October 2001, we applied to increase
Elba Island's initial rates based on a projected cost of approximately $78
million with an anticipated in-service date of December 1, 2001.

     In May 2000, we filed an application with FERC to expand our pipeline
system by 336 million cubic feet of natural gas per day at an estimated cost of
$141 million, to serve new power generation loads being sited by Southern
Company Services in Alabama. Phase I of the project is expected to be in service
in June 2002, and Phase II is expected to be in service in June 2003. We
received a certificate order from FERC in March 2001. In July 2001, FERC
approved an amendment to the project, which reduced its cost slightly. The
Alabama Municipal Distributors Group and others filed an appeal of FERC's orders
authorizing this project in the D.C. Circuit Court of Appeals.

     In April 2001, we filed an application with FERC to expand our north main
line pipeline system to supply transportation demand services to a simple cycle
electric power generation plant in Calhoun County, Alabama for the summer
months, and Alagasco, one of our customers, and the City of Sylacauga during the
winter months. The additional capacity to provide these services will be created
through a combination of construction of new looping lines, replacement or
uprating of existing pipe, and installation of added compression. The estimated
cost of the project is approximately $26 million with an anticipated in-service
date of June 2003.

     In September 2001, FERC issued a Notice of Proposed Rulemaking (NOPR). The
NOPR proposes to apply the standards of conduct governing the relationship
between interstate pipelines and marketing affiliates to all energy affiliates.
The proposed regulations, if adopted by FERC, would dictate how all our energy
affiliates conduct business and interact with our interstate pipelines. We
cannot predict the outcome of the

                                        5
<PAGE>

NOPR, but adoption of the regulations in substantially the form proposed would,
at a minimum, place additional administrative and operational burdens on us.

     In October 2001, we filed an application with FERC to expand our south
system by 359 million cubic feet of natural gas per day at an estimated cost of
$247 million, to serve existing, new and expanded gas-fired electric generation
facilities. The construction will be undertaken in two phases, with a target
in-service date for the Phase I facilities of June 1, 2003, and for the Phase II
facilities of May 1, 2004.

     While we cannot predict with certainty the final outcome or the timing of
the resolution of all of our rates and regulatory matters, we believe the
ultimate resolution of these issues will not have a material adverse effect on
our financial position, results of operations, or cash flows.

5. TRANSACTIONS WITH RELATED PARTIES

     We participate in El Paso's cash management program which matches
short-term cash excesses and requirements of participating affiliates, thus
minimizing total borrowing from outside sources. We had advanced $433 million at
September 30, 2001, at a market rate of interest which was 3.7%. At December 31,
2000, we had advanced $208 million.

     At September 30, 2001, we had accounts receivable from other related
parties of $1 million and $6 million at December 31, 2000. In addition, we had
accounts payable to other related parties of $61 million at September 30, 2001,
versus $11 million at December 31, 2000. These balances were incurred in the
normal course of business.

6. NEW ACCOUNTING PRONOUNCEMENTS NOT YET ADOPTED

  Accounting for Asset Retirement Obligations

     In August 2001, the FASB issued SFAS No. 143, Accounting for Asset
Retirement Obligations. This statement requires companies to record a liability
relating to the retirement and removal of assets used in their business. The
liability is discounted to the present value, and the related asset value is
increased by the amount of the resulting liability. Over the life of the asset,
the liability will be accreted to its future value and eventually extinguished
when the asset is taken out of service. The provisions of this statement are
effective for fiscal years beginning after June 15, 2002. We are currently
evaluating the effects of this pronouncement.

  Accounting for the Impairment or Disposal of Long-Lived Assets

     In October 2001, the FASB issued SFAS No. 144, Accounting for the
Impairment or Disposal of Long-Lived Assets. This statement requires that
long-lived assets that are to be disposed of by sale be measured at the lower of
book value or fair value less cost to sell. The standard also expanded the scope
of discontinued operations to include all components of an entity with
operations that can be distinguished from the rest of the entity and that will
be eliminated from the ongoing operations of the entity in a disposal
transaction. The provisions of this statement are effective for fiscal years
beginning after December 15, 2001. We are currently evaluating the effects of
this pronouncement.

                                        6
<PAGE>

ITEM 2. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
        OF OPERATIONS

     The information contained in Item 2 updates, and you should read it in
conjunction with, information disclosed in Part II, Items 7, 7A, and 8, in our
Annual Report on Form 10-K for the year ended December 31, 2000, in addition to
the financial statements and notes presented in Item 1, Financial Statements, of
this Quarterly Report on Form 10-Q.

                             RESULTS OF OPERATIONS

     During the first quarter of 2000, we completed our sale of Sea Robin
Pipeline Company to comply with an FTC order related to our former parent
company's merger with El Paso. Net proceeds from this sale were $71 million, and
we recognized an extraordinary gain of $12 million, net of income taxes of $9
million. In May 2000, we disposed of our one-third interest in Destin Pipeline
Company to comply with the same FTC order. Net proceeds from this sale were $159
million, and no material gain or loss was recognized on the transaction.

     Below are the operating results and an analysis of these results for the
periods ended September 30:

<Table>
<Caption>
                                                   QUARTER ENDED      NINE MONTHS ENDED
                                                  ----------------    ------------------
                                                   2001      2000      2001       2000
                                                  ------    ------    -------    -------
                                                   (IN MILLIONS, EXCEPT VOLUME AMOUNTS)
<S>                                               <C>       <C>       <C>        <C>
Operating revenues..............................  $   89    $   96    $  294     $  301
Operating expenses..............................     (52)      (60)     (170)      (165)
Other income, net...............................       6         3        18         10
                                                  ------    ------    ------     ------
  Earnings before interest expense and income
     taxes......................................  $   43    $   39    $  142     $  146
                                                  ======    ======    ======     ======
Throughput volumes (BBtu/d)(1)..................   1,692     1,848     1,858      2,105
                                                  ======    ======    ======     ======
</Table>

---------------
(1) BBtu/d means billion British thermal units per day. Throughput volumes
    exclude our Sea Robin pipeline system sold in March 2000 and our one-third
    interest in the Destin system sold in May 2000.

     In March 2000, FERC issued an order allowing us to reactivate our Elba
Island liquefied natural gas facility. Following the order, we made adjustments
approved under a previous FERC order, including re-establishing costs related to
the facility which we were previously ordered to write off and eliminating a
regulatory asset for future recoveries of our Elba Island facility costs. As of
January 1, 2000, we also ceased accumulating amounts to be recovered under a
minimum bill provision under a prior settlement order.

  Third Quarter 2001 Compared to Third Quarter 2000

     Operating revenues for the quarter ended September 30, 2001, were $7
million lower than the same period in 2000. The decrease was due to lower
remarketing rates on released capacity in 2001 as a result of the 2000 rate case
settlement allowing customers to partially reduce their firm transportation
capacity as well as the impact of sales of excess natural gas in 2000. Also
contributing to the decrease were lower prices on sales under natural gas sales
contracts.

     Operating expenses for the quarter ended September 30, 2001, were $8
million lower from the same period in 2000. The decrease was due to lower
operating expenses and lower corporate allocations following El Paso's merger
with The Coastal Corporation in January 2001, lower ad valorem and franchise
taxes in 2001 and lower prices on purchases of natural gas.

     Other income for the quarter ended September 30, 2001, was $3 million
higher than the same period in 2000 due primarily to higher capitalization of
allowance for funds used during the reactivation of Elba Island.

                                        7
<PAGE>

  Nine Months Ended 2001 Compared to Nine Months Ended 2000

     Operating revenues for the nine months ended September 30, 2001, were $7
million lower than the same period in 2000. The decrease was due to the impact
of our 2000 rate case settlement, including lower remarketing rates on released
capacity in 2001 as a result of a partial reduction of the firm transportation
capacity by customers, lower settlement rates and a transportation contract
termination in 2001. Also contributing to the decrease were higher 2000 sales of
excess natural gas, the elimination of the minimum bill provisions on our Elba
Island facility and lower transportation revenues due to the sale of our Sea
Robin system in the first quarter of 2000. These decreases were partially offset
by higher prices on sales under natural gas sales contracts in the first half of
2001.

     Operating expenses for the nine months ended September 30, 2001, were $5
million higher than the same period in 2000. The increase was due to the impact
of higher average prices in the first nine months of 2001 on natural gas
purchase contracts and higher depreciation expenses in 2001 due to the
combination of a one-time favorable adjustment to depreciation during the first
quarter of 2000 as a result of the approval to reactivate our Elba Island
facility and additions of plant assets, partially offset by lower depreciation
following our 2000 rate case settlement. The increase was also partially offset
by lower corporate allocations following El Paso's merger with Coastal,
collection of minimum bill costs associated with maintaining the Elba Island
facility in 2000, lower operating expenses as a result of the sale of Sea Robin
and lower ad valorem and franchise taxes in 2001.

     Other income for the nine months ended September 30, 2001, was $8 million
higher than the same period in 2000 due to the elimination of an asset for the
future recovery of costs established for the Elba Island facility in the first
quarter of 2000, higher capitalization of allowance for funds used during the
reactivation of Elba Island and contract termination fees in the first quarter
of 2001.

NON-AFFILIATED INTEREST AND DEBT EXPENSE

     Non-affiliated interest and debt expense for the quarter and nine months
ended September 30, 2001, was $3 million and $7 million higher than the same
periods in 2000 due to increased long-term borrowings during 2001. See Item 1,
Financial Statements, Note 3 for a further discussion of our borrowing
activities.

AFFILIATED INTEREST INCOME, NET

     Affiliated interest income, net for the nine months ended September 30,
2001, was $10 million higher than the same period in 2000 due to increased
average advances under our cash management program with El Paso in 2001 offset
by lower short-term interest rates. For the quarter ended September 30, 2001,
affiliated interest and debt expense was approximately $1 million higher than
the same period in 2000. During the quarter, higher average balances were
partially offset by lower average rates.

INCOME TAXES

     The income tax expense for the quarters ended September 30, 2001 and 2000,
were $14 million and $13 million resulting in effective tax rates of 41 percent
and 38 percent. The income tax expense for the nine months ended September 30,
2001 and 2000, were $47 million for both periods, resulting in an effective tax
rate of 39 percent for both periods. Our effective tax rates were different than
the statutory rate of 35 percent in all periods due to state income taxes.

                 NEW ACCOUNTING PRONOUNCEMENTS NOT YET ADOPTED

     See Item 1, Financial Statements, Note 6, which is incorporated herein by
reference.

                                        8
<PAGE>

CAUTIONARY STATEMENT FOR PURPOSES OF THE "SAFE HARBOR" PROVISIONS OF THE PRIVATE
                    SECURITIES LITIGATION REFORM ACT OF 1995

     This report contains or incorporates by reference forward-looking
statements within the meaning of the Private Securities Litigation Reform Act of
1995. Where any forward-looking statement includes a statement of the
assumptions or bases underlying the forward-looking statement, we caution that,
while we believe these assumptions or bases to be reasonable and to be made in
good faith, assumed facts or bases almost always vary from the actual results,
and the differences between assumed facts or bases and actual results can be
material, depending upon the circumstances. Where, in any forward-looking
statement, we or our management express an expectation or belief as to future
results, that expectation or belief is expressed in good faith and is believed
to have a reasonable basis. We cannot assure you, however, that the statement of
expectation or belief will result or be achieved or accomplished. The words
"believe," "expect," "estimate," "anticipate" and similar expressions will
generally identify forward-looking statements.

ITEM 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

     This information updates, and you should read it in conjunction with,
information disclosed in Part II, Item 7A in our Annual Report on Form 10-K for
the year ended December 31, 2000, in addition to the information presented in
Items 1 and 2 of this Quarterly Report on Form 10-Q.

     There are no material changes in our quantitative and qualitative
disclosures about market risks from those reported in our Annual Report on Form
10-K for the year ended December 31, 2000.

                                        9
<PAGE>

                          PART II -- OTHER INFORMATION

ITEM 1. LEGAL PROCEEDINGS

     See Part I, Item 1, Financial Information, Note 4, which is incorporated
herein by reference.

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

a. Exhibits

     None.

     Undertaking

          We hereby undertake, pursuant to Regulation S-K, Item 601(b),
     paragraph (4)(iii), to furnish to the U.S. Securities and Exchange
     Commission, upon request, all constituent instruments defining the rights
     of holders of our long-term debt not filed herewith for the reason that the
     total amount of securities authorized under any of such instruments does
     not exceed 10 percent of our total consolidated assets.

b. Reports on Form 8-K

     None.

                                        10
<PAGE>

                                   SIGNATURES

     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.

                                            SOUTHERN NATURAL GAS COMPANY

Date: November 9, 2001                             /s/ GREG G. GRUBER
                                                ---------------------------
                                                       Greg G. Gruber
                                                   Senior Vice President,
                                                Chief Financial Officer and
                                                         Treasurer
                                                 (Chief Accounting Officer)

                                        11