<PAGE>58

                                                                 Exhibit 99

                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                                    FORM 11-K

(Mark One)
(X) ANNUAL REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES
    EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2003
                          ----------------------

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

For the transition period from ______________ to ______________________

Commission file number 2-28286, as exhibit 28.2
                       -------------------------

A. Full title of the plan and the address of the plan, if different from that of
   the issuer named below:
      THE BNA 401(k) PLAN

B. Name of issuer of the securities held pursuant to the plan and the address of
   its principal executive office:

            The Bureau of National Affairs, Inc.
            1231 25th Street, N. W.
            Washington, D. C.  20037

            Index to form 11-K:

            Financial Statements -
            Report of Independent Auditors                           61
            Statements of Net Assets Available for Benefits -
              December 31, 2003 and 2002                             62
            Statements of Changes in Net Assets Available
             for Benefits - Years Ended December 31,
             2003, 2002, and 2001                                    63
            Notes to Financial Statements - December 31,
             2003, 2002, and 2001                                    64
            Schedule of Assets Held for Investment Purposes          67


<PAGE>59




                                    SIGNATURE


            Pursuant to the requirements of the Securities Exchange Act of 1934,
            the BNA 401(k) Plan Administrative Committee has duly caused this
            annual report to be signed by the undersigned thereunto duly
            authorized.

            THE BNA 401(k) PLAN
            ------------------

            Date  March 11, 2004


            By    s/Gilbert S. Lavine
                  ----------------------------------------
                  Gilbert S. Lavine
                  Chairman of the Administrative Committee




<PAGE>60


                               THE BNA 401(k) PLAN

                              Financial Statements

                           December 31, 2003 and 2002

                   (With Independent Auditors' Report Thereon)





<PAGE>61


                          Independent Auditors' Report


The Administrative Committee of
The BNA 401K Plan:

We have audited the accompanying statements of net assets available for benefits
of The BNA 401K Plan (the Plan) as of December 31, 2003 and 2002, and the
related statements of changes in net assets available for benefits for each of
the years in the three-year period ended December 31, 2003, and the supplemental
schedule of assets held for investment purposes as of December 31, 2003. These
financial statements and supplemental schedule are the responsibility of the
Plan's management. Our responsibility is to express an opinion on these
financial statements based on our audits.

We conducted our audits in accordance with auditing standards generally accepted
in the United States of America. Those standards require that we plan and
perform the audit to obtain reasonable assurance about whether the financial
statements are free of material misstatement. An audit includes examining, on a
test basis, evidence supporting the amounts and disclosures in the financial
statements. An audit also includes assessing the accounting principles used and
significant estimates made by management, as well as evaluating the overall
financial statement presentation. We believe that our audits provide a
reasonable basis for our opinion.

In our opinion, the financial statements referred to above present fairly, in
all material respects, the net assets available for benefits of the Plan as of
December 31, 2003 and 2002, and the changes in net assets available for benefits
for each of the years in the three-year period ended December 31, 2003 in
conformity with accounting principles generally accepted in the United States of
America.

Our audits were made for the purpose of forming an opinion on the basic
financial statements taken as a whole. The supplemental schedule of assets held
for investment purposes as of December 31, 2003 is presented for the purpose of
additional analysis and is not a required part of the basic financial statements
but is supplementary information required by the Department of Labor's Rules and
Regulations for Reporting and Disclosure under the Employee Retirement Income
Security Act of 1974. The supplemental schedule has been subjected to the
auditing procedures applied in the audit of the basic financial statements and,
in our opinion, is fairly stated in all material respects in relation to the
basic financial statements taken as a whole.



                              s\ KPMG LLP
                              -----------
                                 KPMG LLP

McLean, VA
March 4, 2004

<PAGE>62



                               THE BNA 401(k) PLAN

                 STATEMENTS OF NET ASSETS AVAILABLE FOR BENEFITS

                           DECEMBER 31, 2003 AND 2002


                                              2003             2002
                                         -------------    -------------
  Cash                                   $     22,371     $     17,774

  Investments, at fair value (Note 2):
    BNA common stock                       88,875,889       85,110,585
    Mutual funds                           15,906,227        9,111,134
    Investment trust                        3,830,240        2,741,284
    Participant notes receivable              651,987          655,245
                                         -------------    -------------
      Total investments                   109,264,343       97,618,248
                                         -------------    -------------
    Net assets available for benefits    $109,286,714     $ 97,636,022
                                         =============    =============







                See accompanying notes to financial statements.


<PAGE>63
                               THE BNA 401(k) PLAN

           STATEMENTS OF CHANGES IN NET ASSETS AVAILABLE FOR BENEFITS

                  YEARS ENDED DECEMBER 31, 2003, 2002, AND 2001



                                             2003          2002        2001
                                        ----------------------------------------
Additions to net assets attributed to:
Investment income (Note 2):
  Dividends                             $  2,660,845  $  2,607,522  $ 2,550,521
  Interest from participant loans             35,356        48,358       56,583
  Net appreciation (depreciation)
    in fair value of:
      BNA common stock                     6,124,230     5,957,875    7,039,817
      Mututal funds                        2,388,827    (1,306,333)    (594,494)
                                        ----------------------------------------
                                          11,209,258     7,307,422    9,052,427
Contributions by participants (Note 1):
  Salary deductions                        6,906,961     6,461,279    6,090,336
  Rollovers                                  265,198       592,555      488,247
                                        ----------------------------------------
Total additions                           18,381,417    14,361,256   15,631,010
                                        ----------------------------------------

Deductions from net assets attributed to:
Distributions to participants (Note 1)     6,726,482     3,958,721    4,536,418
Administrative costs (Note 3)                  4,243         8,195        2,079
                                        ----------------------------------------
 Total deductions                          6,730,725     3,966,916    4,538,497
                                        ----------------------------------------
   Net increase                           11,650,692     10,394340   11,092,513


Net assets available for benefits:
   Beginning of year                      97,636,022    87,241,682   76,149,169
                                        ----------------------------------------
   End of year                          $109,286,714  $ 97,636,022  $87,241,682
                                        ========================================








                See accompanying notes to financial statements.





<PAGE>64


                               THE BNA 401(k) PLAN

                          NOTES TO FINANCIAL STATEMENTS

                  YEARS ENDED DECEMBER 31, 2003, 2002, AND 2001



(1) SUMMARY DESCRIPTION OF PLAN

      The following description of the BNA 401(k) Plan (the "Plan") provides
      only general information. Participants should refer to the Plan agreement
      for a more complete description of the Plan's provisions.

      The Plan is a contributory benefit plan sponsored by The Bureau of
      National Affairs, Inc. (the "Company" or "Plan Sponsor"), for the benefit
      of employees of the Company and certain of its subsidiaries. The Plan was
      established in 1982 with an effective date of January 1, 1983, and is
      subject to the provisions of the Employee Retirement Income Security Act
      of 1974, as amended ("ERISA"). The Plan is designed to provide benefits to
      participants or their beneficiaries, and encourages savings through
      investments in the Company's common stock and various other investment
      options.

      Full-time and part-time employees are eligible to participate in the Plan
      upon completion of thirty days of service. To participate, eligible
      employees authorize the Company to contribute on their behalf, a salary
      reduction amount, subject to certain annual ceiling limitations provided
      in the Plan, by tax laws, and by ERISA. Contributions may begin at the
      next quarterly entry date following the thirty-day service period. The
      Plan also accepts certain rollover contributions.

      The Plan has two trusts. The BNA Stock Trust holds Company stock and the
      Mutual Fund Trust holds all other investments. The trusts maintain
      separate accounts for each participant in the Plan. These accounts are
      credited with the participants' contributions and Plan earnings, and may
      be charged with certain administrative expenses. Participants' accounts
      are fully vested. Distributions can be made in the event of retirement,
      death, qualifying hardships, or other severance of service. If, upon
      terminating employment, a participant's account value exceeds $5,000, the
      participant may opt to delay distribution until reaching age 65.

      An administrative committee appointed by the Company's Board of Directors
      acts as Plan administrator. An officer of the Company serves as the
      Trustee of the BNA Stock Trust. Charles Schwab Trust Company is the
      trustee of the Mutual Fund Trust.

      The Plan maintains its records and prepares its financial statements on
      the accrual basis of accounting. The preparation of financial statements
      requires the use of estimates in accordance with accounting principles
      generally accepted in the United States of America. Actual results could
      differ from those estimates.


(2)   INVESTMENTS

      Upon enrollment in the Plan, a participant may direct contributions to any
      of ten investment options. Participants may change their investment
      options as desired. Investment options include the shares of the Company's
      common stock, a stable value fund, and eight mutual funds of registered
      investment companies that invest in various asset mixes of common stocks,
      debt securities, and/or money market securities.

                                                                     (Continued)

<PAGE>65

                               THE BNA 401(k) PLAN

                          NOTES TO FINANCIAL STATEMENTS

                  YEARS ENDED DECEMBER 31, 2003, 2002, AND 2001


      Mutual funds (shares of registered investment companies) are stated at
      fair value and purchases and sales of investments are recorded on a
      trade-date basis. Shares of the investment trust are valued at quoted
      market prices which represent the net asset value of underlying shares
      held by the Plan at year-end. Participant notes receivable are valued at
      cost which approximates fair value. The fair value of the Company's common
      stock is valued by the Company's Board of Directors semiannually for the
      Stock Purchase and Transfer Plan (SPTP). The Plan values its investments
      in the Company's stock at the price used for SPTP market trades. BNA Class
      A common stock amounted to $73,657,114 and $72,501,387 at December 31,
      2003 and 2002, respectively. BNA Class B common stock amounted to
      $15,158,813 and $12,553,233 at December 31, 2003 and 2002, respectively.
      No other investment exceeded five percent of net assets available for Plan
      benefits as of December 31, 2003 and 2002.

      Ownership and transferability of the Company's Class A, Class B, and Class
      C stock are substantially restricted to current and former employees by
      provisions of the Company's certificate of incorporation. Ownership of
      Class A stock, which is voting, is restricted to active employees. Class B
      stock and Class C stock are nonvoting. No class of stock has preference
      over another upon declaration of dividends or liquidation. The Trust may
      sell Class A common stock, or exchange it for Class B or Class C common
      stock, if necessary to comply with the above ownership restrictions.

      Participants may borrow from their fund accounts a minimum of $1,000 up to
      a maximum of $50,000. Loan terms range from one to five years. The loans
      are secured by the balance in the participant's account and bear interest
      at the Prime rate plus one percent, as determined at the loan's inception.
      At December 31, 2003 interest rates on loans ranged from 5.0% to 10.5%.
      Principal and interest is paid through regular payroll deductions. Loans
      and loan repayments are treated as Plan asset transfers, not as
      distributions and contributions.

(3) ADMINISTRATIVE COSTS

      The Company pays certain administrative costs on behalf of the Plan. Such
      costs, which include custodian and administrator fees, are not reflected
      in the accompanying financial statements. The Plan pays the remaining
      administrative costs.





                                                                     (Continued)

<PAGE>66

                               THE BNA 401(k) PLAN

                          NOTES TO FINANCIAL STATEMENTS

                  YEARS ENDED DECEMBER 31, 2003, 2002, AND 2001


(4) INCOME TAXES

      The Plan received its latest favorable determination letter from the
      Internal Revenue Service, dated September 9, 2002. The letter indicates
      that the Plan, as designed, is qualified under the applicable requirements
      of the Internal Revenue Code. Subsequent to the filing of the Plan for
      review, additional amendments were made to the Plan. The Plan Sponsor
      believes that the Plan as amended is currently designed and is being
      operated in compliance with the Internal Revenue Code, and that the Plan
      qualifies as tax-exempt as of December 31, 2003. Therefore, no provision
      for income taxes is included in the Plan's financial statements.




<PAGE>67


                               THE BNA 401(k) PLAN

                 Schedule of Assets Held for Investment Purposes
                                December 31, 2003

 $ or                                                                Fair
Shares    Quantity    Identity and description of investment         Value
--------  ---------   ------------------------------------------  ------------

                      Cash and Cash Equivalents
                      -------------------------

$            22,371   Cash                                        $     22,371
                                                                  ------------

                      BNA Common Stock
                      ----------------
* Shares  6,547,299   Class A                                       73,657,114
* Shares  1,347,450   Class B                                       15,158,813
* Shares      5,330   Class C                                           59,962
         ----------                                               ------------
*         7,900,079    Total BNA Common Stock                       88,875,889
         ----------                                               ------------

                      Mutual Funds
                      --------------
 Shares     56,425    Artisan Mid Cap Fund                           1,454,630
 Shares    279,857    PIMCO Total Return Fund                        2,997,269
*Shares     96,509    Schwab Market Manager International            1,228,556
 Shares     74,880    T Rowe Price Personal Strategy-Balanced        1,237,016
 Shares     72,325    T Rowe Price Personal Strategy-Growth          1,396,570
 Shares     31,049    T Rowe Price Personal Strategy-Income            430,646
 Shares     68,054    Torray Fund                                    2,720,804
 Shares     43,253    Vanguard Index Trust 500 Portfolio             4,440,736
                                                                  ------------
                      Total Mutual Funds                            15,906,227
                                                                  ------------


                      Investment Trust
                      ------------------
*Shares    259,068    Charles Schwab Stable Value Fund               3,830,240
                                                                  ------------

                      Loans
                      -----
                      Participant Notes Receivable
* $        651,987   (Interest rates ranging from 5.0% to 10.5%)       651,987
                                                                  ------------
                      Total Assets                                $109,286,714
                                                                  ============


*     Party-in-Interest to the Plan


                  See accompanying Independent Auditor's Report.