<PAGE>   1
                                    FORM 10-Q
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549



             ( X ) Quarterly Report Pursuant to Section 13 or 15(d)
                     of the Securities Exchange Act of 1934

                For the quarterly period ended September 26, 1999

                                       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 : 000-23457


                        ENTEX INFORMATION SERVICES, INC.

             (Exact name of registrant as specified in its charter)


    Delaware                                                    13-3715291
(State or other jurisdiction                                 (I.R.S. Employer
   of incorporation)                                     Identification Number)

                6 International Drive, Rye Brook, N.Y. 10573-1058
                                 (914) 935-3600

   (Address, including zip code and telephone number, including area code, of
                          principal executive offices)

     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 and Exchange
     Act of 1934 during the preceding twelve months, and (2) has been subject to
     such filing requirements for the past ninety days: YES ( X ) NO ( )

     The number of outstanding shares of the Registrant's Common Stock, par
     value $.0001 per share, was 32,477,108 (excluding 82,500 treasury shares)
     on October 24, 1999.

     As filed with the Securities and Exchange Commission on November 10, 1999
________________________________________________________________________________
<PAGE>   2
                        ENTEX INFORMATION SERVICES, INC.

                                      INDEX

                                                                   Page Numbers
                                                                   ------------
     PART I.      FINANCIAL INFORMATION

     Item 1.      Financial Statements

                  Consolidated Balance Sheets as of
                  September 26, 1999 and June 27, 1999                     2

                  Consolidated Statements of Operations
                  for the Three months Ended September 26, 1999
                  and September 27, 1998                                   3

                  Condensed Consolidated Statements of Cash Flows for
                  the Three Months Ended September 26, 1999
                  and September 27, 1998                                   4

                  Notes to Condensed Consolidated Financial Statements     5

     Item 2.      Management's Discussion and Analysis of Financial
                  Condition and Results of Operations                    6 - 10

     Item 3.      Quantitative and Qualitative Disclosures About
                  Market Risk                                              11


     PART II.     OTHER INFORMATION

     Item 6.      Exhibits and Reports on Form 8-K                         12

                  Signatures                                               13
<PAGE>   3
                        ENTEX INFORMATION SERVICES, INC.
                         PART I - FINANCIAL INFORMATION
                           Consolidated Balance Sheets
                    (Dollars in thousands except share data)

<TABLE>
<CAPTION>

                                                                  Unaudited
                                                                   Sept 26,          June 27,
                                                                     1999             1999
                                                                  ----------        ---------
                                     ASSETS
<S>                                                               <C>               <C>
Current assets:
   Cash and cash equivalents                                       $   1,975        $  12,546
   Trade receivables (net of allowance for doubtful accounts
         of $4,342 and $4,905, respectively)                         106,131          142,533
   Vendor receivables (net of allowance of $3,073 and $4,013,
         respectively)                                                 1,209            5,066
   Inventory                                                          14,191           13,939
   Other current assets                                                9,603           10,214
                                                                   ---------        ---------
Total current assets                                                 133,109          184,298

Property, plant and equipment, net                                    31,167           33,699
Goodwill (net of accumulated amortization
      of  $3,560 and $3,311, respectively)                            10,612           10,860
Other assets, net                                                      4,644            4,898
                                                                   ---------        ---------
Total assets                                                       $ 179,532        $ 233,755
                                                                   =========        =========
           LIABILITIES AND STOCKHOLDERS' EQUITY (DEFICIT)

Current liabilities:
   Accounts payable                                                $  32,605        $  49,842
   Accrued liabilities                                                52,371           57,935
   Obligations related to discontinued operations                      6,688           12,421
   Obligations related to restructuring                                3,287            4,933
   Notes payable and current installments of long-term debt           79,495          104,049
                                                                   ---------        ---------
          Total current liabilities                                  174,446          229,180
                                                                   =========        =========

Long-term debt                                                       124,088          124,252
Other long-term liabilities                                              260              294
                                                                   ---------        ---------
          Total long-term liabilities                                124,348          124,546
                                                                   ---------        ---------

Total liabilities                                                    298,794          353,726
                                                                   ---------        ---------

Stockholders' equity (deficit):
Preferred stock, 2 million shares authorized;
  no shares issued or outstanding                                       --                 --
Common stock, $.0001 par value; 100 million shares
    authorized, 32,473,762 and 32,437,070 shares issued and                3                3
    outstanding, respectively
Additional paid-in capital                                            19,706           19,594
Retained earnings (deficit)                                         (138,888)        (139,485)
Treasury stock, shares at cost                                            (2)              (2)
Cumulative translation adjustments                                       (81)             (81)
                                                                   ---------        ---------
Total stockholders' equity (deficit)                                (119,262)        (119,971)
                                                                   =========        =========

Total liabilities & stockholders' equity (deficit)                 $ 179,532        $ 233,755
                                                                   =========        =========
</TABLE>

See accompanying notes to condensed consolidated financial statements.

                                     Page 2
<PAGE>   4
                        ENTEX INFORMATION SERVICES, INC.
                      Consolidated Statements of Operations
                  (Dollars in thousands except per share data)




<TABLE>
<CAPTION>
                                                                            Unaudited
                                                                        Three Months Ended
                                                                ----------------------------------
                                                                September 26,        September 27,
                                                                     1999                 1998
                                                                -------------        -------------
<S>                                                              <C>                 <C>
      Net revenues                                               $    123,597        $    113,849

      Cost of services provided                                        93,697              83,093
                                                                 ------------        ------------

      Gross profit                                                     29,900              30,756

      Selling, general and administrative expenses                     27,695              40,648
                                                                 ------------        ------------

              Income (loss) from operations                             2,205              (9,892)

      Interest expense, net                                             5,639               9,695
      Other income                                                     (1,235)                 --
                                                                 ------------        ------------

      Loss from continuing operations before income taxes              (2,199)            (19,587)

      Provision for income taxes                                            4                   1
                                                                 ------------        ------------

               Loss from continuing operations                         (2,203)            (19,588)

      Discontinued operations:
         Income from operations (net of income tax expense)             2,800               5,788
                                                                 ------------        ------------

             Net income (loss)                                   $        597        $    (13,800)
                                                                 ============        ============

      Common share data:
      Basic and diluted earnings (loss) per common share:
      Continuing operations                                      $      (0.07)       $      (0.61)
      Discontinued operations                                            0.09                0.18
                                                                 ------------        ------------

      Net income (loss)                                          $       0.02        $      (0.43)
                                                                 ============        ============

      Basic and diluted weighted average number of
         shares of common stock outstanding                        32,452,634          32,402,154
                                                                 ============        ============
</TABLE>


     See accompanying notes to condensed consolidated financial statements.


                                     Page 3
<PAGE>   5
                        ENTEX INFORMATION SERVICES, INC.
                 Condensed Consolidated Statements of Cash Flows
                             (Dollars in thousands)


<TABLE>
<CAPTION>
                                                                                Unaudited
                                                                           Three Months Ended
                                                                     -----------------------------
                                                                     September 26,   September 27,
                                                                         1999             1998
                                                                     -------------   -------------
<S>                                                                  <C>             <C>
      Net cash provided by operating activities                        $ 13,906        $   7,162
                                                                       --------        ---------

      Cash flows from investing activities:
          Capital expenditures                                           (1,253)          (8,593)
                                                                       --------        ---------
                   Net cash used in investing activities                 (1,253)          (8,593)
                                                                       --------        ---------

      Cash flows from financing activities:
          Proceeds from borrowings                                          320          132,306
          Change in cash overdraft                                        1,774           (3,527)
          Proceeds from sale of common stock, net                           112             --
          Payments on notes payable and long-term debt                  (25,430)        (132,177)
                                                                       --------        ---------
                 Net cash used in financing activities                  (23,224)          (3,398)
                                                                       --------        ---------

      Decrease in cash equivalents                                      (10,571)          (4,829)
      Cash and cash equivalents at beginning of period                   12,546           14,265
                                                                       --------        ---------

      Cash and cash equivalents at end of period                       $  1,975        $   9,436
                                                                       ========        =========

      Supplemental disclosure of cash flow information:
         Cash paid during the period for:
         Interest payments                                             $  9,386        $   8,566
                                                                       ========        =========

         Tax payments                                                  $      3        $     587
                                                                       ========        =========
</TABLE>


     See accompanying notes to condensed consolidated financial statements.


                                     Page 4
<PAGE>   6
                        ENTEX INFORMATION SERVICES, INC.
              Notes to Condensed Consolidated Financial Statements



1.   BASIS OF PRESENTATION

     The unaudited condensed consolidated financial statements included herein
     have been prepared by the Company pursuant to the rules and regulations of
     the Securities and Exchange Commission. Certain information and footnote
     disclosures normally included in financial statements prepared in
     accordance with generally accepted accounting principles have been
     condensed or omitted pursuant to such rules and regulations. However, in
     the opinion of management of the Company, the condensed consolidated
     financial statements include all adjustments, which consist only of normal
     recurring accruals, necessary to present fairly the financial information
     for such periods. These condensed consolidated financial statements should
     be read in conjunction with the consolidated financial statements and the
     notes thereto included in the Company's Annual Report on Form 10-K for the
     fiscal year ended June 27, 1999.

     Cash equivalents include short-term, highly liquid investments with a
     maturity of three months or less from the date of acquisition.

     Reclassifications of prior-year data have been made, where appropriate, to
     conform to the current year presentation.

     The results of operations for the three months ended September 26, 1999 are
     not necessarily indicative of the results to be expected for the fiscal
     year ending July 2, 2000.

2.   COMPREHENSIVE INCOME

     Effective for the quarter ended September 27, 1998, the Company adopted
     Statement of Financial Accounting Standards No. 130, "Reporting
     Comprehensive Income" ("FAS 130"). Comprehensive income includes both net
     income and other comprehensive income. Included in other comprehensive
     income are foreign currency translation gains (losses). In accordance with
     the disclosure requirements of FAS 130, comprehensive income (loss) for the
     three months ended September 26, 1999 and September 27, 1998 was $597 and
     $(13,771) respectively. Other comprehensive income (loss) for the three
     months ended September 26, 1999 and September 27, 1998 was $0 and $29,
     respectively.


                                     Page 5
<PAGE>   7
                        ENTEX INFORMATION SERVICES, INC.
           Management's Discussion and Analysis of Financial Condition
                           and Results of Operations

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

OVERVIEW

ENTEX, a company engaged in principally one line of business, is a leading
provider of distributed computing management solutions to meet the support
requirements of Fortune 1000 companies and other large enterprises for their
local-area networks, wide-area networks, and end-users. ENTEX provides a single
source of service for its customers' personal computer ("PC") and server
platforms including system design, operations support and change management.

This section contains trend analysis and other forward-looking statements based
on current expectations. Actual results may differ materially due to a number of
factors. Reference is made to the Company's Annual Report on Form 10-K for a
further discussion of certain business factors.

RESULTS OF OPERATIONS

The following table sets forth the percentage of net revenues represented by the
items in the Company's statements of operation for the periods indicated:

<TABLE>
<CAPTION>
                                                    Three Months Ended
                                                ----------------------------
                                                September 26,  September 27,
                                                    1999          1998
                                                -------------  -------------
<S>                                             <C>            <C>
          Net revenues                              100.0%        100.0%
                                                    -----         -----

          Cost of services provided                  75.8          73.0

          Selling, general and administrative
              expenses                               22.4          35.7
                                                    -----         -----

          Income (loss) from operations               1.8          (8.7)

          Interest expense, net                       4.6           8.5

          Other income                               (1.0)           --
                                                    -----         -----

          Loss from continuing
              operations before income taxes         (1.8)        (17.2)

          Provision for income taxes                   --            --
                                                    -----         -----

          Loss from continuing
               operations                            (1.8)        (17.2)

          Discontinued operations                     2.3           5.1
                                                    -----         -----

          Net income (loss)                            .5%        (12.1)%
                                                    =====         =====
</TABLE>


                                     Page 6
<PAGE>   8
                        ENTEX INFORMATION SERVICES, INC.
           Management's Discussion and Analysis of Financial Condition
                           and Results of Operations



THREE MONTHS ENDED SEPTEMBER 26, 1999 COMPARED TO THREE MONTHS ENDED
SEPTEMBER 27, 1998

     Consolidated net income for the three months ended September 26, 1999 was
$.6 million compared to consolidated net loss of $13.8 million in the three
months ended September 27, 1998. The improved results from operations
principally results from lower selling, general and administrative expenses.

     Revenues: Revenues were $123.6 million for the three months ended September
26, 1999 as compared to $113.8 million for the three months ended September 27,
1998, an increase of $9.8 million or 8.6%. The increase reflects increased
demand from existing customers and the addition of new large accounts.

     Gross margin: Gross margin was 24.2% or $29.9 million for the current
quarter as compared to 27.0% or $30.8 million for the three months ended
September 27, 1998. The decline is principally driven by the classification of
direct overhead costs for servicing large customers in cost of services provided
in 1999 which costs were classified in SG&A in 1998, and higher spending for
third party costs for short term projects.

     Selling, general and administrative expenses: Selling, general and
administrative expenses as a percentage of revenues decreased to 22.4% for the
quarter ended September 26, 1999 from 35.7% in the same period a year ago. For
the three months ended September 26, 1999, selling, general and administrative
expenses were $27.7 million as compared to $40.6 million for the quarter ended
September 27, 1998, a decrease of $12.9 million, primarily reflecting cost
reductions realized as a result of the reorganization announced in the second
quarter ended December 27, 1998 and classification of direct overhead costs of
servicing large customers to cost of services provided.

     Income (loss) from operations: Income from operations was $2.2 million for
the three months ended September 26, 1999 as compared to a loss from operations
of $9.9 million in the quarter ended September 27, 1998.

     Interest expense, net: Net interest expense decreased to $5.6 million for
the three months ended September 26, 1999 as compared to $9.7 million for the
three months ended September 27, 1998. The decrease is due to decreased working
capital needs as a result of the sale of the TAS Division partially offset by
higher borrowing rates associated with the 12 1/2% Senior Subordinated Notes due
2006.

     Other income: Other income for the quarter ended September 26, 1999,
represents a $1.2 million gain on the early retirement of debt.

     Discontinued operations: Income from discontinued operations was $2.8
million for the three months ended September 26, 1999. This compares to income
from discontinued operations of $5.8 million in the quarter ended September 27,
1998. The income from operations of $2.8 million reflects better than
anticipated recovery on vendor receivables.

     Net income (loss): As a result of the factors mentioned above, the net
income for the three months ended September 26, 1999 was $.6 million as compared
to net loss of $13.8 million for the three months ended September 27, 1998.


                                     Page 7
<PAGE>   9
                        ENTEX INFORMATION SERVICES, INC.
           Management's Discussion and Analysis of Financial Condition
                           and Results of Operations

LIQUIDITY AND CAPITAL RESOURCES

     The Company finances its operations principally with borrowings under the
IBMCC Working Capital Line of Credit with IBM Credit Corporation. Cash provided
by operating activities was $13.9 million for the three months ended September
26, 1999 compared to $7.2 million for three months ended September 27, 1998.

     Cash provided by operations during the three months ended September 26,
1999 resulted primarily from the net income, depreciation and other non-cash
charges to income and from changes in operating assets and liabilities,
principally receivables of the TAS Division.

     Cash used in investing activities (capital expenditures) was $1.3 million
during the three months ended September 26, 1999 compared with $8.6 million
during the three months ended September 27, 1998.

     Cash used in financing activities was $23.2 million during the three months
ended September 26, 1999 compared to $3.4 million during the three months ended
September 27, 1998. During the three months ended September 26, 1999, cash
received from wind down of the TAS Division receivables were used to pay down
interest bearing debt. During July 1998, the Company issued $100 million of 12
1/2% Senior Subordinated Notes due 2006. The net proceeds were used to repay
outstanding indebtedness of the Company, resulting in an increase in working
capital of approximately $74 million.

     As of September 26, 1999, the Company's primary source of liquidity
consisted of financing provided by IBMCC. The IBMCC Working Capital Line of
Credit is asset based, and provides for borrowings of up to $150 million subject
to available collateral. The interest bearing portion was $77.5 million as of
September 26, 1999. The amount of available borrowings and such line of credit
expire on July 31, 2001, and can be reduced or terminated by IBMCC upon 60 days'
prior notice. Amounts outstanding under the IBMCC Working Capital Line of Credit
bear interest at LIBOR plus 3.00% (8.3% at September 26, 1999). As previously
reported, the borrowing base under the IBMCC Working Capital Line of Credit had
been expanded through November 9, 1999 to allow up to $20 million in excess of
what would otherwise have been allowed under collateral formulas (the
"overadvance"). The overadvance bears interest at LIBOR plus 4% (9.3% at
September 26, 1999). The overadvance has been extended through November 30, 1999
and the Company is currently in the process of negotiating an additional
extension. Assuming the continued availability of the IBMCC Working Capital Line
of Credit, including the overadvance, management believes that the amount which
will be available to it thereunder will meet the Company's liquidity needs for
the next 12 months. Should the terms of the extension of the overadvance
restrict use of borrowed funds, the Company may need to raise alternative or
additional funds through public or private equity or debt financing or from
other sources to meet certain financial commitments. However, there can be no
assurance that the Company will be able to raise such additional funding.

     The IBMCC Financing Agreement contains restrictive covenants with respect
to maintenance of minimum tangible net worth, current ratio and fixed charge
coverage. In addition, the IBMCC Financing Agreement prohibits the Company from
paying cash dividends on common stock. At September 26, 1999, the Company was in
compliance with such covenants.

     At September 26, 1999, the Company had no material commitments other than
obligations under its credit facilities, term notes and operating lease
facilities.


                                     Page 8
<PAGE>   10
                        ENTEX INFORMATION SERVICES, INC.
           Management's Discussion and Analysis of Financial Condition
                           and Results of Operations


YEAR 2000 READINESS

     The Company uses a significant number of computer software programs and
operating systems in its internal operations, including applications used in
financial business systems and various administration functions. As the Year
2000 approaches, each of these computer systems may be affected in some way by
the rollover of the two-digit year value to 00. From that point forward, if
these systems are unable to properly recognize date sensitive information, they
could generate erroneous data or fail. The Company is utilizing both internal
and external resources to identify, correct or reprogram and test the systems
for Year 2000 compliance.

     ENTEX classifies its Year 2000 project into five phases: inventory,
assessment, renovation, validation and implementation. Inventory is the process
in which all electronic/computer components are defined for all systems
(information technology and non-information technology). Assessment is the
process in which all components are classified as either "Y2K-ready" or not.
Renovation is the process in which systems undergo necessary upgrades,
replacements or are retired. Validation is the process in which compliant
systems are tested within the Company's infrastructure to validate that either
the readiness assessment is correct or that the renovated system or component
can be integrated without causing or being affected by a Year 2000 impact.
Implementation is the process in which a prepared system is installed into the
Company's production environment and is utilized to support business operations.

     The Company completed an inventory of its applications systems in December
1997. More than 30 systems were identified, prioritized according to criticality
to then-current business operations, and assessed for readiness status. Based on
this review, the Company scheduled each system for either renovation, validation
or replacement. An initiative was also begun to install certain modules in the
SAP R/3 (TM) Enterprise Requirements Planning (ERP) product to address Year 2000
preparedness in many of the systems identified in the Company's inventory. In
December 1998 the Company abandoned implementation of SAP R/3 (TM) and has
written off its investment of $10.7 million. An effort to replace the Company's
core financial reporting system is underway and is expected to be completed by
April 1, 2000. The current environment has been validated and will remain in
place until final cutover is complete. Validation and implementation of the one
remaining mission critical system that has not yet been tested in our
environment is scheduled for completion by December 1, 1999.

     Effective May 10, 1999, the Company sold certain assets of the TAS
Division. The applications and systems used in support of that portion of
business were maintained through August 13, 1999. Efforts with regard to "Y2K
readiness" for such applications and systems were either completed before the
sale or have been halted as a result of the sale. Renovation and validation
activities have been reduced to address only those remaining in the ongoing
business.

     Assessments have been completed in the processing and telecommunications
environments. A similar activity in the employee desktop environment was
completed in March 1999. The Company's inventory and assessment of its non-IT
systems (facilities and security systems) was completed in April 1999, and was
made "Y2K-ready" before September 30, 1999.


                                     Page 9
<PAGE>   11
                        ENTEX INFORMATION SERVICES, INC.
           Management's Discussion and Analysis of Financial Condition
                           and Results of Operations


     Contingency plans have been developed for specific business processes and
related applications in the event the Company experiences outages of up to a
five day duration resulting from the failure of a system to properly address the
Year 2000 issue. Such plans are based on the Company's assessment of its ability
to successfully make and validate all required changes and upgrades. The worst
case scenario involves outages that exceed five business days and extend
indefinitely. The Company is committed to supplementing the existing contingency
plans with long-term plans in the event that successful validation of
applications changes and upgrades has not occurred by November 15, 1999 or
December 1, 1999 in the case of the one mission critical system that has not
yet been validated and implemented.

     Total costs to complete the Company's Year 2000 efforts for ongoing
operations are estimated at approximately $4.3 million. As of October 31, 1999,
the Company has spent approximately $3.9 million. The remaining amount is for
providing staff contingency support through March 2000.

     In addition to upgrading its own systems, the Company has contacted certain
significant customers and suppliers to determine their Year 2000 compliance
profile. To date the Company has not received any information, which would
indicate that the Year 2000 will result in any significant disruption from such
customers and suppliers.

     All potential risks and uncertainties associated with the Year 2000 issue
cannot be fully and accurately quantified. Contingency plans will be developed
if third party data interchange partners fail compliance testing or if the
replacement or renovation of other existing systems is not on schedule. Although
the Company does not believe that any additional costs or potential loss in
revenue associated with Year 2000 readiness initiatives will have a material
adverse effect on the Company's business, operating results or financial
condition, there can be no assurance that the costs necessary to update software
or potential systems interruptions would not have a material adverse effect on
the Company's business, operating results and financial condition.


                                     Page 10
<PAGE>   12
                        ENTEX INFORMATION SERVICES, INC.


Item 3. QUANTITATIVE AND QUALITATIVE DISCLOSURE ABOUT MARKET RISK

         The Company is exposed to interest rate risk primarily through its
         asset based financing agreement. The Company utilizes these borrowings
         to meet its working capital needs. As of September 26, 1999, the
         Company had borrowings of approximately $77.5 outstanding, which have a
         variable interest rate of 8.3%. Using a yield to maturity analysis and
         assuming an increase in interest rate on these borrowings of 25 basis
         points, future annual cash flows would be effected by $.2 million. All
         other borrowings are at fixed interest rates and therefore market
         interest rate variability does not impact their future cash flows.

         Currently, the Company does not enter into financial instruments for
         trading or other speculative purposes or to manage interest rate
         exposure.


                                     Page 11
<PAGE>   13
                           PART II - OTHER INFORMATION



Item 6. EXHIBITS AND REPORTS ON FORM 8-K

         (a)   Exhibits required by Item 601 of Regulation S-K.

               (27)   Financial Data Schedule.


         (b)   ENTEX filed no reports on Form 8-K during the first fiscal
               quarter ended September 26, 1999.


                                     Page 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 hereunto duly authorized.




                                       ENTEX Information Services, Inc.
                                       --------------------------------
                                                 (Registrant)



November 10, 1999                      Michael G. Archambault
                                       ---------------------------------
                                       Michael G. Archambault
                                       Senior Vice President, CFO and Treasurer



November 10, 1999                      Shirley S. Mehta
                                       ---------------------------------
                                       Shirley S. Mehta
                                       Vice President and Controller


                                     Page 13