<PAGE>   1

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

                                 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 JUNE 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 1-4101

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

                         TENNESSEE GAS PIPELINE COMPANY
             (Exact Name of Registrant as Specified in its Charter)

<Table>
<S>                                            <C>
                   DELAWARE                                      74-1056569
         (State or Other Jurisdiction                         (I.R.S. Employer
      of Incorporation or Organization)                     Identification No.)

               EL PASO BUILDING
            1001 LOUISIANA STREET
                HOUSTON, TEXAS                                     77002
   (Address of Principal Executive Offices)                      (Zip Code)
</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 $5 per share. Shares outstanding on August 6, 2001:
208

     TENNESSEE GAS PIPELINE 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>   2

                        PART I -- FINANCIAL INFORMATION

ITEM 1. FINANCIAL STATEMENTS

                         TENNESSEE GAS PIPELINE COMPANY

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

<Table>
<Caption>
                                                          QUARTER ENDED       SIX MONTHS ENDED
                                                             JUNE 30,             JUNE 30,
                                                          --------------      ----------------
                                                          2001      2000      2001       2000
                                                          ----      ----      -----      -----
<S>                                                       <C>       <C>       <C>        <C>
Operating revenues......................................  $170      $185      $384       $381
                                                          ----      ----      ----       ----
Operating expenses
  Operation and maintenance.............................    56        60       112        124
  Depreciation, depletion, and amortization.............    33        34        66         69
  Taxes, other than income taxes........................    12        11        25         23
                                                          ----      ----      ----       ----
                                                           101       105       203        216
                                                          ----      ----      ----       ----
Operating income........................................    69        80       181        165
                                                          ----      ----      ----       ----
Other income
  Earnings from unconsolidated affiliates...............     2         2         7          6
  Other, net............................................     5         2         5          5
                                                          ----      ----      ----       ----
                                                             7         4        12         11
                                                          ----      ----      ----       ----
Income before interest and income taxes.................    76        84       193        176
                                                          ----      ----      ----       ----
Non-affiliated interest and debt expense................    29        27        57         61
Affiliated interest income, net.........................    (1)       (3)       --        (14)
Income taxes............................................    13        20        41         43
                                                          ----      ----      ----       ----
                                                            41        44        98         90
                                                          ----      ----      ----       ----
Net income..............................................  $ 35      $ 40      $ 95       $ 86
                                                          ====      ====      ====       ====
</Table>

                            See accompanying notes.

                                        1
<PAGE>   3

                         TENNESSEE GAS PIPELINE COMPANY

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

<Table>
<Caption>
                                                              JUNE 30,   DECEMBER 31,
                                                                2001         2000
                                                              --------   ------------
<S>                                                           <C>        <C>
                                       ASSETS
Current assets
  Cash and cash equivalents.................................   $    4       $    4
  Accounts and notes receivable, net
    Customer................................................      190          210
    Affiliates..............................................       54           60
    Other...................................................      111           98
  Materials and supplies....................................       20           19
  Deferred income taxes.....................................        4           12
  Other.....................................................       12           14
                                                               ------       ------
         Total current assets...............................      395          417
                                                               ------       ------
Property, plant, and equipment, at cost.....................    2,706        2,612
Less accumulated depreciation, depletion, and
  amortization..............................................      396          347
                                                               ------       ------
                                                                2,310        2,265
Additional acquisition cost assigned to utility plant,
  net.......................................................    2,281        2,292
                                                               ------       ------
         Total property, plant, and equipment, net..........    4,591        4,557
                                                               ------       ------
Other assets
  Investments in unconsolidated affiliates..................      150          135
  Other.....................................................       77           95
                                                               ------       ------
                                                                  227          230
                                                               ------       ------
         Total assets.......................................   $5,213       $5,204
                                                               ======       ======

LIABILITIES AND STOCKHOLDER'S EQUITY
Current liabilities
  Accounts payable
    Trade...................................................   $  178       $  198
    Affiliates..............................................       36           18
    Other...................................................       37           47
  Short-term borrowings.....................................      168          215
  Taxes payable.............................................      144          124
  Deferred credits..........................................       23           42
  Other.....................................................       34           28
                                                               ------       ------
         Total current liabilities..........................      620          672
                                                               ------       ------
Long-term debt..............................................    1,355        1,354
                                                               ------       ------
Other
  Deferred income taxes.....................................    1,167        1,144
  Other.....................................................      234          292
                                                               ------       ------
                                                                1,401        1,436
                                                               ------       ------
Commitments and contingencies
Stockholder's equity
  Common stock, par value $5 per share; authorized 300
    shares; issued 208 shares...............................       --           --
  Additional paid-in capital................................    1,405        1,405
  Retained earnings.........................................      432          337
                                                               ------       ------
         Total stockholder's equity.........................    1,837        1,742
                                                               ------       ------
         Total liabilities and stockholder's equity.........   $5,213       $5,204
                                                               ======       ======
</Table>

                            See accompanying notes.

                                        2
<PAGE>   4

                         TENNESSEE GAS PIPELINE COMPANY

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

<Table>
<Caption>
                                                              SIX MONTHS ENDED
                                                                  JUNE 30,
                                                              -----------------
                                                               2001       2000
                                                              ------      -----
<S>                                                           <C>         <C>
Cash flows from operating activities
  Net income................................................   $95        $ 86
  Adjustments to reconcile net income to net cash from
     operating activities
     Depreciation, depletion, and amortization..............    66          69
     Undistributed earnings of unconsolidated affiliates....    (7)         (6)
     Deferred income tax expense............................    31          36
  Working capital changes, net of non-cash transactions.....    (9)        (45)
  Other.....................................................   (65)         26
                                                               ---        ----
          Net cash provided by operating activities.........   111         166
                                                               ---        ----
Cash flows from investing activities
  Purchases of property, plant, and equipment...............   (96)        (56)
  Additions to investments..................................    (8)         --
  Net change in other affiliated advances receivable........    24         442
  Other.....................................................     1          (3)
                                                               ---        ----
          Net cash provided by (used in) investing
           activities.......................................   (79)        383
                                                               ---        ----
Cash flows from financing activities
  Net repayments of commercial paper........................   (47)       (514)
  Net change in other affiliated advances payable...........    15         (35)
                                                               ---        ----
          Net cash used in financing activities.............   (32)       (549)
                                                               ---        ----
Net change in cash and cash equivalents.....................    --          --
Cash and cash equivalents
  Beginning of period.......................................     4           4
                                                               ---        ----
  End of period.............................................   $ 4        $  4
                                                               ===        ====
</Table>

                            See accompanying notes.

                                        3
<PAGE>   5

                         TENNESSEE GAS PIPELINE 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 June 30,
2001, and for the quarters and six months ended June 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 businesses. 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. DEBT AND OTHER CREDIT FACILITIES

     At June 30, 2001, our weighted average interest rate on short-term
borrowings was 4.6%, and at December 31, 2000, it was 7.6%. We had the following
short-term borrowings:

<Table>
<Caption>
                                                              JUNE 30,   DECEMBER 31,
                                                                2001         2000
                                                              --------   ------------
                                                                   (IN MILLIONS)
<S>                                                           <C>        <C>
Commercial paper............................................    $168         $215
                                                                ====         ====
</Table>

     In June 2001, El Paso Corporation replaced its $2 billion, 364-day
revolving credit facility with a renewable $3 billion, 364-day revolving credit
and competitive advance facility. We are a designated borrower under this
facility and, as such, are liable for any amounts outstanding under this
facility. The interest rate varies and was LIBOR plus 50 basis points at June
30, 2001. No amounts were outstanding under this facility at June 30, 2001.

     As of June 30, 2001, we have $200 million of capacity remaining under our
shelf registration statement on file with the Securities and Exchange
Commission.

3. COMMITMENTS AND CONTINGENCIES

  Legal Proceedings

     In February 1998, the United States and the state of Texas filed in a U.S.
District Court a Comprehensive Environmental Response, Compensation and
Liability Act (CERCLA) cost recovery action against 14 companies, including us
and some of our current and former affiliates, related to the Sikes Disposal
Pits Superfund Site located in Harris County, Texas. The suit claims that the
United States and the state of Texas have spent over $125 million in remediating
Sikes and seeks to recover that amount plus interest from the defendants to the
suit. The Environmental Protection Agency (EPA) has recently indicated that it
may seek an additional amount up to $30 million, plus interest, in indirect
costs from the defendants under a new cost allocation methodology. Defendants
are challenging this allocation policy. Although an investigation relating to
Sikes is ongoing, we believe that the amount of material, if any, disposed at
Sikes by us was small,

                                        4
<PAGE>   6

possibly de minimis. However, the plaintiffs have alleged that the defendants
are each jointly and severally liable for the entire remediation costs and have
also sought a declaration of liability for future response costs such as
groundwater monitoring. Settlement discussions are ongoing.

     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.

     In November 1988, the Kentucky environmental agency filed a complaint in a
Kentucky state court alleging that we discharged pollutants into the waters of
the state and disposed of polychlorinated biphenyls (PCBs) without a permit. The
agency sought an injunction against future discharges, an order to remediate or
remove PCBs, and a civil penalty. We entered into agreed orders with the agency
to resolve many of the issues raised in the original allegations and received
water discharge permits from the agency for our Kentucky compressor stations.
The relevant Kentucky compressor stations are being characterized and remediated
under a 1994 consent order with the EPA.

     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.

     While the outcome of the matters discussed above cannot be predicted with
certainty, we do not expect the ultimate resolution of these matters will have a
material adverse effect on our 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 June 30, 2001, we had a reserve of approximately $96 million for
expected remediation costs. In addition, we expect to make capital expenditures
for environmental matters of approximately $83 million in the aggregate for the
years 2001 through 2006. These expenditures primarily relate to compliance with
clean air regulations.

     Since 1988, we have been engaged in an internal project to identify and
deal with the presence of PCBs and other substances, including those on the EPA
List of Hazardous Substances, at compressor stations and other facilities we
operate. While conducting this project, we have been in frequent contact with
federal and state regulatory agencies, both through informal negotiation and
formal entry of consent orders, to ensure that our efforts meet regulatory
requirements.

     In May 1995, following negotiations with our customers, we filed a
Stipulation and Agreement (the Environmental Stipulation) with the Federal
Energy Regulatory Commission (FERC) that established a

                                        5
<PAGE>   7

mechanism for recovering a substantial portion of the environmental costs
identified in our internal project. The Environmental Stipulation was effective
July 1, 1995, and all amounts have been collected from customers. Refunds may be
required to the extent actual eligible expenditures are less than amounts
collected.

     We are a party in proceedings involving federal and state authorities
regarding the past use of a lubricant containing PCBs in our starting air
systems. We executed a consent order in 1994 with the EPA governing the
remediation of relevant compressor stations and are working with the EPA and the
relevant states regarding those remediation activities. We are also working with
the Pennsylvania and New York environmental agencies regarding remediation and
post-remediation activities at the Pennsylvania and New York stations.

     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 four active
sites under the CERCLA or state equivalents. We have sought to resolve our
liability as a PRP at these CERCLA sites, as appropriate, through
indemnification by third parties and/or settlements which provide for payment of
our allocable share of remediation costs. As of June 30, 2001, we have estimated
our share of the remediation costs at these sites to be between approximately $1
million and $2 million and have provided reserves that we believe are adequate
for such costs. Since the cleanup costs are estimates and are subject to
revision as more information becomes available about the extent of remediation
required, and because in some cases we have asserted a defense to any liability,
our estimates could change. Moreover, liability under the federal CERCLA statute
is joint and several, meaning that we could be required to pay in excess of our
pro rata share of remediation costs. Our understanding of the financial strength
of other PRPs has been considered, where appropriate, in the determination of
our estimated liabilities. We presently believe that the costs associated with
these CERCLA sites will not have a material adverse effect on our financial
position, operating results, or cash flows.

     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. For a further discussion of specific environmental
matters, see Legal Proceedings above.

  Rates and Regulatory Matters

     In April 1997, FERC approved the settlement of all issues related to the
recovery of our Gas Supply Realignment (GSR) and other transition costs. Under
the agreement, we are entitled to collect up to $770 million from our customers,
$693 million through a demand surcharge and $77 million through an interruptible
transportation surcharge. Our final GSR report was approved by the FERC on May
16, 2001. In June 2001, $31 million of the amount collected through the demand
surcharge was refunded to our firm transportation contract customers. As of June
30, 2001, $56 million of the interruptible transportation surcharge had been
collected. There is no time limit for collection of the remaining interruptible
transportation surcharge. This agreement also provides for a rate case
moratorium that expired November 2000 and an escalating rate cap, indexed to
inflation, through October 2005, for some of our customers.

     Our current tariff structure was established through a settlement approved
by FERC in October 1996. This settlement included a rate design change that
resulted in a larger portion of our transportation revenues being dependent on
throughput. Following this settlement, one of our competitors filed an appeal
arguing that our cost allocation methodology deters the development of market
centers. On August 11, 2000, we and that

                                        6
<PAGE>   8

competitor jointly filed a proposed settlement to resolve this issue. The
settlement provided for a discount on the transportation rates for receipts at
the interconnect shared by us and them. On October 17, 2000, an Administrative
Law Judge certified the settlement and submitted the settlement to FERC for
approval. On February 8, 2001, FERC issued an order approving the settlement. On
April 11, 2001, FERC issued an order granting our request for clarification on
their February 8, 2001 order, and no requests for rehearing were filed on the
clarification.

     We have over 500 contracts with more than 200 different customers for firm
transportation to various points on our system, with terms varying from one
month to over 10 years. Our portfolio of firm contracts has an average term in
excess of 5 years. Our business has shifted from a traditional dependence solely
on long-term contracts into a portfolio approach which balances short-term
opportunities with long-term commitments. This shift is due to changes in market
conditions and competition driven by state utility deregulation, local
distribution company mergers, new supply sources, volatility in gas prices,
demand in short-term capacity, and new markets in power plants. These changes
will create uncertainty in our transportation business; however, they will
provide more opportunities for us in marketing our system to new growth segments
such as gas-fired electric generation.

     We will continue to evaluate the application of regulatory accounting
principles as there are changes in the regulatory and economic environment.
Factors that may influence this assessment are:

     - inability to recover cost increases due to rate caps and rate case
       moratoriums;

     - inability to recover capitalized costs, including an adequate return on
       those costs through the ratemaking process;

     - excess capacity;

     - discounting rates in the markets we serve; and

     - impacts of ongoing initiatives in, and deregulation of, the natural gas
       industry.

     While we cannot predict with certainty the final outcome or 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.

4. 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 borrowed $15 million at
June 30, 2001, at a market rate of interest which was 4.2%. At December 31,
2000, we had advanced $34 million. In addition, we had notes receivable from
other related parties of $18 million at June 30, 2001, and $9 million at
December 30, 2000.

     At June 30, 2001, we had accounts receivable from other related parties of
$36 million and $17 million at December 31, 2000. In addition, we had accounts
payable to other related parties of $21 million at June 30, 2001, versus $18
million at December 31, 2000. These balances were incurred in the normal course
of business.

                                        7
<PAGE>   9

5. NEW ACCOUNTING PRONOUNCEMENTS NOT YET ADOPTED

  Business Combinations

     In July 2001, the Financial Accounting Standards Board (FASB) issued
Statement of Financial Accounting Standards (SFAS) No. 141, Business
Combinations. This statement requires that all transactions that fit the
definition of a business combination be accounted for using the purchase method
and prohibits the use of the pooling of interests method for all business
combinations initiated after June 30, 2001. This statement also establishes
specific criteria for the recognition of intangible assets separately from
goodwill and requires unallocated negative goodwill to be written off
immediately as an extraordinary item. This standard will have an impact on any
business combination we undertake in the future. We are currently evaluating the
effects of this pronouncement on our historical financial statements.

  Goodwill and Other Intangible Assets

     In July 2001, the FASB issued SFAS No. 142, Goodwill and Other Intangible
Assets. This statement requires that goodwill no longer be amortized but
intermittently tested for impairment at least on an annual basis. Other
intangible assets are to be amortized over their useful life and reviewed for
impairment in accordance with the provisions of SFAS No. 121, Accounting for the
Impairment of Long-Lived Assets and Long-Lived Assets to be Disposed of. An
intangible asset with an indefinite useful life can no longer be amortized until
its useful life becomes determinable. This statement has various effective
dates, the most significant of which is January 1, 2002. We are currently
evaluating the effects of this pronouncement.

  Accounting for Asset Retirement Obligations

     In July 2001, the FASB approved for issuance 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.

                                        8
<PAGE>   10

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

     Below are the operating results and an analysis of those results for the
quarters and six months ended June 30:

<Table>
<Caption>
                                                               QUARTER ENDED      SIX MONTHS ENDED
                                                             -----------------   -------------------
                                                              2001      2000       2001       2000
                                                             -------   -------   --------   --------
                                                              (IN MILLIONS, EXCEPT VOLUME AMOUNTS)
<S>                                                          <C>       <C>       <C>        <C>
Operating revenues.........................................  $  170    $  185     $  384     $  381
Operating expenses.........................................    (101)     (105)      (203)      (216)
Other income...............................................       7         4         12         11
                                                             ------    ------     ------     ------
  Earnings before interest and income taxes................  $   76    $   84     $  193     $  176
                                                             ======    ======     ======     ======
Throughput volumes (BBtu/d)(1).............................   4,111     4,027      4,589      4,447
                                                             ======    ======     ======     ======
</Table>

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

(1) BBtu/d means billion British thermal units per day.

  Second Quarter 2001 Compared to Second Quarter 2000

     Operating revenues for the quarter ended June 30, 2001, were $15 million
lower than the same period in 2000. The decrease was due to lower 2001 revenues
resulting from contract remarketing during 2000 and lower rates on throughput in
2001 as a result of a higher proportion of short versus long hauls compared to
2000. Also contributing to the decrease were contract quantity reductions or
cancellations on our pipeline system by customers of East Tennessee Natural Gas
Company resulting from the FTC's order to El Paso to sell its East Tennessee
system in the first quarter of 2000. Partially offsetting the decrease was the
impact of higher prices on sales of excess natural gas in 2001.

     Operating expenses for the quarter ended June 30, 2001, were $4 million
lower than the same period in 2000. The decrease was due to lower depreciation
expenses resulting from the retirement of assets and lower corporate allocations
and operating expenses as a result of cost savings following El Paso's merger
with The Coastal Corporation in January 2001.

  Six Months Ended 2001 Compared to Six Months Ended 2000

     Operating revenues for the six months ended June 30, 2001, were $3 million
higher than the same period in 2000. The increase was due to the impact of
higher prices on sales of excess natural gas in 2001, partially offset by lower
2001 revenues resulting from contract remarketing during 2000, lower rates on
throughput in 2001 as a result of a higher proportion of short versus long hauls
compared to 2000, and contract quantity reductions or cancellations on our
pipeline system by customers of East Tennessee.

     Operating expenses for the six months ended June 30, 2001, were $13 million
lower than the same period in 2000. The decrease was due to lower project
development costs, lower depreciation expenses resulting from the retirement of
assets, and lower corporate allocations and operating expenses as a result of
cost savings following El Paso's merger with Coastal.

                                        9
<PAGE>   11

NON-AFFILIATED INTEREST AND DEBT EXPENSE

     Non-affiliated interest and debt expense for the quarter ended June 30,
2001, was $2 million higher than the same period in 2000 primarily due to
increased commercial paper activities in the second quarter of 2001 offset by
lower short-term interest rates.

     Non-affiliated interest and debt expense for the six months ended June 30,
2001, was $4 million lower than the same period in 2000 primarily due to lower
average commercial paper activities for the first six months of 2001, lower
short-term interest rates in 2001, and increased capitalized interest due to
higher capital project expenditures in 2001.

AFFILIATED INTEREST INCOME, NET

     Affiliated interest income, net for the quarter and six months ended June
30, 2001, was $2 million and $14 million lower than the same periods in 2000 due
to lower short-term interest rates and decreased average advances to El Paso in
2001 under our cash management program.

INCOME TAXES

     The income tax expenses for the quarters ended June 30, 2001 and 2000, were
$13 million and $20 million, resulting in effective tax rates of 27 percent and
33 percent. The income tax expenses for the six months ended June 30, 2001 and
2000, were $41 million and $43 million, resulting in effective tax rates of 30
percent and 33 percent. Our effective tax rates were different than the
statutory rate of 35 percent in all periods primarily due to state income taxes.

OTHER

     In February 2001, we received and accepted a FERC order issuing a
certificate for the Stagecoach Expansion project. The project will connect the
Stagecoach Storage Field in Tioga County, New York, to our mainline at our
compressor station 319 in Bradford County, Pennsylvania. The new lateral will
consist of 23.7 miles of pipe and have a capacity of 500 million cubic feet per
day (MMcf/d). In addition, the project will expand our 300 Line to provide 90
MMcf/d of firm transportation service from station 319 to its interconnect with
New Jersey Natural in Passaic, New Jersey. The cost of these facilities is
estimated to be $80 million, and the facilities are planned to be completed
November 1, 2001 subject to the timely receipt of remaining permits and
regulatory approvals. During the quarter ended June 30, 2001, $12 million was
spent on the Stagecoach Expansion project. Total year to date expenditures have
been $15 million.

     In June 2001, we purchased an additional 11 percent interest in the
Portland Natural Gas Transmission partnership from two exiting partners for a
purchase price of approximately $9 million. This purchase increased our
ownership interest from approximately 19 percent to approximately 30 percent.

                 NEW ACCOUNTING PRONOUNCEMENTS NOT YET ADOPTED

     See Item 1, Financial Statements, Note 5, which is incorporated herein by
reference.

                                        10
<PAGE>   12

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.

                                        11
<PAGE>   13

                          PART II -- OTHER INFORMATION

ITEM 1. LEGAL PROCEEDINGS

     See Part I, Item 1, Financial Statements, Note 3, 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

     Each exhibit identified below is filed as a part of this report. Exhibits
not incorporated by reference to a prior filing are designated by an asterisk;
all exhibits not so designated are incorporated herein by reference to a prior
filing as indicated.

<Table>
<Caption>
        EXHIBIT
        NUMBER                            DESCRIPTION
        -------                           -----------
        <S>       <C>
        *10.A     -- $3,000,000,000 364-Day Revolving Credit and Competitive
                  Advance Facility Agreement, dated as of June 11, 2001, by
                     and among El Paso Corporation, El Paso Natural Gas
                     Company, Tennessee Gas Pipeline Company, the several
                     banks and other financial institutions from time to time
                     parties to the Agreement, The Chase Manhattan Bank, ABN
                     Amro Bank, N.V., and Citibank, N.A., as co-documentation
                     agents for the Lenders, and Bank of America, N.A. and
                     Credit Suisse First Boston, as co-syndication agents for
                     the Lenders.
</Table>

     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.

                                        12
<PAGE>   14

                                   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.

                                            TENNESSEE GAS PIPELINE COMPANY

Date: August 10, 2001                              /s/ GREG G. GRUBER
                                            ------------------------------------
                                                       Greg G. Gruber
                                                   Senior Vice President
                                                and Chief Financial Officer

Date: August 10, 2001                             /s/ JEFFREY I. BEASON
                                            ------------------------------------
                                                     Jeffrey I. Beason
                                            Senior Vice President and Controller
                                                 (Chief Accounting Officer)

                                        13
<PAGE>   15

                               INDEX TO EXHIBITS

     Each exhibit identified below is filed as a part of this report. Exhibits
not incorporated by reference to a prior filing are designated by an asterisk;
all exhibits not so designated are incorporated herein by reference to a prior
filing as indicated.

<Table>
<Caption>
        EXHIBIT
         NUMBER                                  DESCRIPTION
        -------                                  -----------
<C>                      <S>
         *10.A           -- $3,000,000,000 364-Day Revolving Credit and Competitive
                            Advance Facility Agreement, dated as of June 11, 2001, by
                            and among El Paso Corporation, El Paso Natural Gas
                            Company, Tennessee Gas Pipeline Company, the several
                            banks and other financial institutions from time to time
                            parties to the Agreement, The Chase Manhattan Bank, ABN
                            Amro Bank, N.V., and Citibank, N.A., as co-documentation
                            agents for the Lenders, and Bank of America, N.A. and
                            Credit Suisse First Boston, as co-syndication agents for
                            the Lenders.
</Table>

                                        14