<PAGE>   1

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549



                                    Form 10-Q



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



                  For the Quarterly Period Ended March 31, 2000


                           Commission File No. 1-8032



                          SAN JUAN BASIN ROYALTY TRUST


Texas                                                      I.R.S. No. 75-6279898


                     Bank One, Texas, N.A., Trust Department
                                 P. O. Box 2604
                             Fort Worth, Texas 76113

                          Telephone Number 817/884-4630



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
                                       ---    ---

Number of units of beneficial interest outstanding at May 8, 2000:   46,608,796



                                  Page 1 of 15




<PAGE>   2

                          SAN JUAN BASIN ROYALTY TRUST

                         PART I - FINANCIAL INFORMATION


Item 1.  Financial Statements.

The condensed financial statements included herein have been prepared by Bank
One, Texas, N.A. as Trustee for the San Juan Basin Royalty Trust (the "Trust"),
without audit, pursuant to the rules and regulations of the Securities and
Exchange Commission. Certain information and footnote disclosures normally
included in annual financial statements have been condensed or omitted pursuant
to Rule 10-01 of Regulation S-X promulgated under the Securities and Exchange
Act of 1934, although the Trustee believes that the disclosures are adequate to
make the information presented not misleading. These condensed financial
statements should be read in conjunction with the financial statements and the
notes thereto included in the Trust's annual report on Form 10-K for the year
ended December 31, 1999. In the opinion of the Trustee, all adjustments,
consisting only of normal recurring adjustments, necessary to present fairly the
assets, liabilities and trust corpus of the San Juan Basin Royalty Trust at
March 31, 2000, and the distributable income and changes in trust corpus for the
three-month periods ended March 31, 2000 and 1999 have been included. The
distributable income for such interim periods is not necessarily indicative of
the distributable income for the full year.

Deloitte & Touche LLP, independent certified public accountants, has conducted a
limited review of the condensed financial statements as of March 31, 2000 and
for the three-month periods ended March 31, 2000 and 1999 included herein.

                                      - 2 -



<PAGE>   3

INDEPENDENT ACCOUNTANTS' REPORT


Bank One, Texas, N.A. as Trustee
   for the San Juan Basin Royalty Trust:

We have reviewed the accompanying condensed statement of assets, liabilities and
trust corpus of the San Juan Basin Royalty Trust as of March 31, 2000 and the
related condensed statements of distributable income and changes in trust corpus
for the three-month periods ended March 31, 2000 and 1999. These financial
statements are the responsibility of the Trustee.

We conducted our reviews in accordance with standards established by the
American Institute of Certified Public Accountants. A review of interim
financial information consists principally of applying analytical procedures to
financial data and making inquiries of persons responsible for financial and
accounting matters. It is substantially less in scope than an audit conducted in
accordance with generally accepted auditing standards, the objective of which is
the expression of an opinion regarding the financial statements taken as a
whole. Accordingly, we do not express such an opinion.

The accompanying condensed financial statements are prepared on a modified cash
basis as described in Note 1, which is a comprehensive basis of accounting other
than generally accepted accounting principles.

Based on our reviews, we are not aware of any material modifications that should
be made to such condensed financial statements for them to be in conformity with
the basis of accounting described in Note 1.

We have previously audited, in accordance with generally accepted auditing
standards, the statement of assets, liabilities and trust corpus of the San Juan
Basin Royalty Trust as of December 31, 1999, and the related statements of
distributable income and changes in trust corpus for the year then ended (not
presented herein); and in our report dated March 22, 1999, we expressed an
unqualified opinion on those financial statements. In our opinion, the
information set forth in the accompanying condensed statement of assets,
liabilities and trust corpus as of December 31, 1999 is fairly stated, in all
material respects, in relation to the statement of assets, liabilities and trust
corpus from which it has been derived.




DELOITTE & TOUCHE LLP

May 10, 2000

                                      - 3 -
<PAGE>   4
SAN JUAN BASIN ROYALTY TRUST

CONDENSED STATEMENTS OF ASSETS, LIABILITIES AND TRUST CORPUS
--------------------------------------------------------------------------------

<TABLE>
<CAPTION>

                                                             March 31,    December 31,
ASSETS                                                         2000           1999
                                                            (Unaudited)
<S>                                                         <C>           <C>
Cash and short-term investments                             $ 2,794,650   $ 3,862,453
Net overriding royalty interest in producing
   oil and gas properties (net of accumulated
   amortization of $89,303,422 and $88,089,329
   at March 31, 2000 and December 31, 1999, respectively)    43,972,106    45,186,199
                                                            -----------   -----------

                                                            $46,766,756   $49,048,652
                                                            ===========   ===========

LIABILITIES AND TRUST CORPUS

Distribution payable to Unit holders                        $ 2,794,650   $ 3,862,453
Commitments and contingencies
Trust corpus - 46,608,796 Units of beneficial
   interest authorized and outstanding                       43,972,106    45,186,199
                                                            -----------   -----------

                                                            $46,766,756   $49,048,652
                                                            ===========   ===========
</TABLE>

CONDENSED STATEMENTS OF DISTRIBUTABLE INCOME (UNAUDITED)
--------------------------------------------------------------------------------

<TABLE>
<CAPTION>

                                                       Three Months Ended
                                                           March 31,
                                                   -------------------------
                                                      2000          1999

<S>                                                <C>           <C>
Royalty income                                     $10,076,594   $ 7,045,206
Interest income                                         24,495        13,626
                                                   -----------   -----------
                                                    10,101,089     7,058,832

General and administrative expenditures                212,586       266,949
                                                   -----------   -----------

Distributable income                               $ 9,888,503   $ 6,791,883
                                                   ===========   ===========

Distributable income per Unit (46,608,796 Units)   $   .212160   $   .145721
                                                   ===========   ===========
</TABLE>


The accompanying notes to condensed financial statements are an integral part of
these statements.


                                     - 4 -

<PAGE>   5
SAN JUAN BASIN ROYALTY TRUST

CONDENSED STATEMENTS OF CHANGES IN TRUST CORPUS (UNAUDITED)
--------------------------------------------------------------------------------
<TABLE>
<CAPTION>

                                                       Three Months Ended
                                                           March 31,
                                                  ----------------------------
                                                     2000              1999

<S>                                               <C>             <C>
Trust corpus, beginning of period                 $ 45,186,199    $ 51,088,020
Amortization of net overriding royalty interest     (1,214,093)     (1,373,933)
Distributable income                                 9,888,503       6,791,883
Distributions declared                              (9,888,503)     (6,791,883)
                                                  ------------    ------------

Trust corpus, end of period                       $ 43,972,106    $ 49,714,087
                                                  ============    ============
</TABLE>


The accompanying notes to condensed financial statements are an integral part of
this statement.

                                     - 5 -
<PAGE>   6
SAN JUAN BASIN ROYALTY TRUST

NOTES TO CONDENSED FINANCIAL STATEMENTS (UNAUDITED)
--------------------------------------------------------------------------------


1.   BASIS OF ACCOUNTING

     The San Juan Basin Royalty Trust was established as of November 1, 1980.
     The financial statements of the Trust are prepared on the following basis:

     o    Royalty income recorded for a month is the amount computed and paid by
          the working interest owner, Burlington Resources Oil & Gas Company
          ("BROG"), to the Trustee for the Trust. Royalty income consists of the
          amounts received by the owner of the interest burdened by the net
          overriding royalty interest ("Royalty") from the sale of production
          less accrued production costs, development and drilling costs,
          applicable taxes, operating charges, and other costs and deductions,
          multiplied by 75%.

     o    Trust expenses recorded are based on liabilities paid and cash
          reserves established from Royalty income for liabilities and
          contingencies.

     o    Distributions to Unit holders are recorded when declared by the
          Trustee.

     o    The conveyance which transferred the overriding royalty interest to
          the Trust provides that any excess of production costs over gross
          proceeds must be recovered from future net profits.

     The financial statements of the Trust differ from financial statements
     prepared in accordance with generally accepted accounting principles
     ("GAAP") because revenues are not accrued in the month of production;
     certain cash reserves may be established for contingencies which would not
     be accrued in financial statements prepared in accordance with GAAP; and
     amortization of the Royalty calculated on a unit-of-production basis is
     charged directly to trust corpus.

2.   FEDERAL INCOME TAXES

     For federal income tax purposes, the Trust constitutes a fixed investment
     trust which is taxed as a grantor trust. A grantor trust is not subject to
     tax at the trust level. The Unit holders are considered to own the Trust's
     income and principal as though no trust were in existence. The income of
     the Trust is deemed to have been received or accrued by each Unit holder at
     the time such income is received or accrued by the Trust rather than when
     distributed by the Trust.

     The Royalty constitutes an "economic interest" in oil and gas properties
     for federal income tax purposes. Unit holders must report their share of
     the revenues of the Trust as ordinary income from oil and gas royalties and
     are entitled to claim depletion with respect to such income. The Royalty is
     treated as a single property for depletion purposes.

     The Trust has on file technical advice memoranda confirming the tax
     treatment described above.

     The Trust began receiving royalty income from coal seam gas wells beginning
     in 1989. Under Section 29 of the Internal Revenue Code, coal seam gas
     production from wells drilled prior to January 1, 1993 (including certain
     wells recompleted in coal seams formations thereafter), generally qualifies
     for the federal income tax credit for producing non-conventional fuels if
     such production and the sale thereof occurs before January 1, 2003. For
     1999, this tax credit was approximately $1.04 per MMBtu. To benefit from
     the credit, each Unit holder must determine from the tax information he
     receives from the Trust his pro rata share of qualifying production of the
     Trust, based upon the number of Units owned during each month of the year,
     and the amount of available credit per MMbtu for the year, and then apply
     the tax credit against his own income tax liability, but such credit may
     not reduce his regular tax liability (after the foreign tax credit and
     certain other nonrefundable credits) below his tentative minimum tax.
     Section 29


                                      - 6 -
<PAGE>   7

     also provides that any amount of Section 29 credit disallowed for the tax
     year solely because of this limitation will increase his credit for prior
     year minimum tax liability, which may be carried forward indefinitely as a
     credit against the taxpayer's regular tax liability, subject, however, to
     the limitations described in the preceding sentence. There is no provision
     for the carryback or carryforward of the Section 29 credit in any other
     circumstances.

     The Trustee is provided summary Section 29 tax credit information related
     to Trust properties by BROG, which information is then passed along to the
     Unit holders. In Nielson-True Partnership, et al, v. Commissioner, a 1997
     Tax Court decision, the court ruled that nonconventional fuel (such as coal
     seam gas) produced from a well drilled and completed in an otherwise
     qualifying formation prior to December 31, 1992, is not eligible for the
     Section 29 credit unless the producer has received an appropriate well
     category determination from the Federal Energy Regulatory Commission
     ("FERC"). On March 23, 1999, the U. S. Court of Appeals for the 10th
     Circuit affirmed that decision. Dictum (i.e., language in the appeals
     court's decision which is not binding as precedent) even suggests that,
     contrary to the clear implications of a 1993 Internal Revenue Service
     ruling, lack of such a well category determination may render the Section
     29 credit unavailable in respect of production from wells recompleted in a
     qualified formation after January 1, 1993, the date that FERC's authority
     to render well category determinations ended (so that obtaining the
     requisite determination for any such well was impossible). Many producers
     assert that wells meeting the definitional requirements applied by FERC in
     rendering well category determinations are eligible for the Section 29
     credit regardless of whether a well category determination is actually
     applied for or received, particularly for wells recompleted in qualifying
     formations after January 1, 1993, and additional litigation (and perhaps a
     legislative initiative) on this issue is to be expected. In fact, on
     December 23, 1999, a petition was filed with the FERC by a coalition of
     energy producers seeking reinstatement of the certification process. By
     letter dated January 14, 2000, the U. S. Department of Energy expressed its
     support of that petition and on January 27, 2000, the FERC issued notice of
     proposed rulemaking by which its regulations would be amended to reinstate
     certain regulations involving well category determinations for Section 29
     tax credits for certain well recompletions commenced after January 1, 1993.

     In some cases the extent to which production from the various coal seam gas
     wells in which the Trust holds an interest would qualify for the Section 29
     credit under the standards applied in the Nielson-True case is unclear, and
     the Trustee has requested that BROG provide clarification and an assessment
     of the effects of the foregoing, if any, on the Trust and its Unit holders.
     Pending such clarification and assessment, or further developments, or
     both, however, the availability of Section 29 credits to Unit holders in
     respect of some portion of the Trust's coal seam gas production could be
     subject to debate and challenge.

     The classification of the Trust's income for purposes of the passive loss
     rules may be important to a Unit holder. As a result of the Tax Reform Act
     of 1986, royalty income will generally be treated as portfolio income and
     will not reduce passive losses.

3.   CONTINGENCIES

     See Part II - Item 1 Legal Proceedings concerning the status of litigation
     matters.

4.   UNDERCHARGE OF CAPITAL EXPENDITURES AND LEASE OPERATING EXPENSES

     Based on its year-end review, BROG has determined that since January of
     1999, BROG has undercharged the Trust for both capital expenditures and
     lease operating charges related to properties burdened by the Trust but not
     operated by BROG. BROG reports that for the 1999 reporting period, these
     charges were approximately $1,200,000 for lease operating charges and
     $500,000 for capital expenditures. For the 2000 reporting period, the
     undercharges are reported to be $500,000 for lease operating charges and
     $140,000 for capital expenditures. BROG multiplies these aggregate expenses
     by the Trust's 75% interest in the Underlying Properties and indicates it
     will pass through additional charges of approximately $1,800,000 in the
     distributions to the Trust for April and May of 2000. The


                                      - 7 -
<PAGE>   8
     Trust's consultants will review cost reporting data and advise the Trust as
     to the proposed pass through of additional charges.

                                     ******

ITEM 2.  TRUSTEE'S DISCUSSION AND ANALYSIS

FORWARD-LOOKING INFORMATION

Certain information included in this report contains, and other materials filed
or to be filed by the Trust with the Securities and Exchange Commission (as well
as information included in oral statements or other written statements made or
to be made by the Trust) may contain or include, forward-looking statements
within the meaning of Section 21E of the Securities Exchange Act of 1934, and
Section 27A of the Securities Act of 1933. Such forward looking statements may
be or may concern, among other things, capital expenditures, drilling activity,
development activities, production efforts and volumes, hydrocarbon prices and
the results thereof, and regulatory matters. Such forward looking statements
generally are accompanied by words such as "may," "will," "estimate," "expect,"
"predict," "anticipate," "goal," "should," "assume," "believe," "plan,"
"intend," or other words that convey the uncertainty of future events or
outcomes. Such statements reflect our current view with respect to future
events; are based on our assessment of, and are subject to, a variety of factors
deemed relevant by the Trustee and involve risks and uncertainties. Should one
or more of these risks or uncertainties occur, actual results may vary
materially and adversely from those anticipated.



                                     - 8 -
<PAGE>   9

THREE MONTHS ENDED MARCH 31, 2000 AND 1999:

The Trust received royalty income of $10,076,594 and interest income of $24,495
during the first quarter of 2000. After deducting administrative expenses of
$212,586 distributable income for the quarter was $9,888,503 ($.212160 per
Unit). In the first quarter of 1999, royalty income was $7,045,206, interest
income was $13,626, administrative expenses were $266,949 and distributable
income was $6,791,883 ($.145721 per Unit). The tax credit relating to production
from coal seam wells totaled approximately $.04 per Unit for the first quarter
of 2000 and $.04 per Unit for the first quarter of 1999. For further information
concerning this tax credit, Unit holders should refer to the Trust's Annual
Report for 1999. Based on 46,608,796 Units outstanding, the per Unit
distributions during the first quarter of 2000 were as follows:

<TABLE>

<S>                                   <C>
January                               $    .089499
February                                   .062701
March                                      .059960
                                      ------------

Quarter Total                         $    .212160
                                      ============
</TABLE>


The royalty income distributed in the first quarter of 2000 was higher than that
distributed in the first quarter of 1999, primarily due to an increase in the
average gas price from $1.54 per Mcf for the first quarter of 1999 to $2.24 per
Mcf for the first quarter of 2000. Interest earnings for the quarter ended March
31, 2000, as compared to the quarter ended March 31, 1999, were higher,
primarily due to an increase in funds available for investment. Administrative
expenses were less, primarily as a result of differences in timing of the
receipt and payment of these expenses.

The capital costs attributable to the properties from which the Trust's 75% net
overriding royalty ("Royalty") was carved (the "Underlying Properties") for the
first quarter of 2000 were reported by BROG as $4,583,126. BROG advised the
Trust that capital expenditures for 2000 are estimated to be $20,500,000.
Capital expenditures were $2,273,201 for the first quarter of 1999.

Based on its year-end review, BROG has determined that since January of 1999,
BROG has undercharged the Trust for both capital expenditures and lease
operating charges related to properties burdened by the Trust's Royalty but not
operated by BROG. BROG reports that for the 1999 reporting period, these charges
were approximately $1,200,000 for lease operating charges and $500,000 for
capital expenditures. For the 2000 reporting period, the undercharges are
reported to be $500,000 for lease operating charges and $140,000 for capital
expenditures. BROG multiplies these aggregate expenses by the Trust's 75%
Royalty interest in the Underlying Properties and indicates it will include
additional charges of approximately $1,800,000 in calculating the distributions
to the Trust for April and May of 2000. The Trust's consultants will review cost
reporting data and advise the Trust as to the proposed pass through of
additional charges.

BROG has informed the Trustee that 7 gross (3.41 net) conventional wells, 3
gross (1.14 net) conventional recompletions and 13 gross (.07 net) coal seam
well recavitations were completed as of March 31, 2000. Sixty-six gross (23.17)
net conventional wells, and 26 gross (8.07 net) conventional recompletions were
in progress during the first quarter of 2000. Ten gross (4.10 net) coal seam
wells, 17 gross (0.11 net) coal seam recavitations and 7 gross (.90 net) coal
seam recompletions were in progress as of March 31, 2000. "Gross" acres or
wells, for purposes of this discussion, means the entire ownership interest of
all parties in such properties, and BROG's interest therein is referred to as
the "net" acres or wells.


                                     - 9 -
<PAGE>   10

Royalty income for the quarter ended March 31, 2000 is associated with actual
gas and oil production during November 1999 through January 2000 from the
Underlying Properties. Gas and oil sales from the Underlying Properties for the
quarters ended March 31, 2000 and 1999 were as follows:

<TABLE>
<CAPTION>

                                                                                    2000         1999
<S>                                                                              <C>          <C>
Gas:
   Total sales (Mcf)                                                             10,080,596   10,337,439
   Mcf per day                                                                      109,572      112,363
   Average price (per Mcf)                                                       $     2.24   $     1.54

Oil:
   Total sales (Bbls)                                                                23,290       18,446
   Bbls per day                                                                         253          201
   Average price (per Bbl)                                                       $    22.48   $     9.63

Gas and oil sales attributable to the Royalty for the quarters ended March 31,
2000 and 1999 were as follows:

Gas sales (Mcf)                                                                   4,743,297    5,043,882
Oil sales (Bbls)                                                                     11,104        9,018
</TABLE>

Gas sales attributable to the Royalty decreased in the first quarter of 2000, as
compared to the same period in 1999. BROG has indicated that, commencing in
January of 1999, deficiencies in its new internal accounting system precluded it
from generating actual production reports and it instead relied upon estimates
based on historical production, which estimates proved high. Prior period
adjustments were employed by BROG to reconcile the difference between its
estimates and the actual production for the subject months. The Trust's
consultants are reviewing data supplied by BROG in support of the prior period
adjustments and have preliminarily approved them, subject to final audit.

Since the oil and gas sales attributable to the Royalty are based on an
allocation formula that is dependent on such factors as price and cost,
including capital expenditures, the aggregate production volumes from the
Underlying Properties may not provide a meaningful comparison to volumes
attributable to the Royalty.

During the first quarter of 2000, gas prices were higher than during the first
quarter of 1999. Gas sales attributable to the Royalty decreased in 2000 as
compared to 1999. The price per barrel of oil during the first quarter of 2000
was $12.85 per bbl higher than that received for the first quarter of 1999 due
to increases in oil prices in world markets generally including the posted
prices applicable to oil sales attributable to the Royalty.

BROG has entered into a contract dated November 10, 1999, for the sale of all
volumes of gas which are subject to the Royalty (the "Trust gas") to Duke Energy
and Marketing L.L.C. That contract provides for the delivery of Trust gas at
various delivery points over a period commencing January 1, 2000, and ending
October 31, 2001, and provides for the sale of Trust gas at prices which
fluctuate in accordance with published indices for gas sold in the San Juan
Basin of New Mexico. Unit holders are referred to Note 6 of the Notes to
Financial Statements in the Trust's 1999 Annual Report for further information
concerning the marketing of gas produced from the Underlying Properties.

In February 1999, the Trust's consultants notified the Trust of an
apparent gas imbalance. A gas imbalance occurs where more than one party is
entitled to the economic benefit of the production of natural gas, but the gas
is sold for the account of less than all of the parties. The resulting imbalance
may be corrected by various means including a cash settlement and/or a volume
adjustment whereby an increased percentage of future production is sold for the
account of the underproduced party or parties. The Trust's


                                     - 10 -
<PAGE>   11
consultants suggested that the subject imbalance might relate to the
acquisition by BROG's predecessor, Southland Royalty Company ("Southland
Royalty"), of mineral properties which had been operated under a Joint Operating
Agreement between Southland Royalty and Unicon, the seller of the properties.
The Trust made inquiry of BROG concerning the imbalance and BROG agreed to
investigate the records. The Trustee met with BROG representatives in June 1999
to discuss the investigation and by correspondence of September 24, 1999, BROG
reported that the imbalance probably related to problems experienced in the
1980's and early 1990's by Southland Royalty and Unicon in their dealings with
Public Service Company of New Mexico. BROG reported that Unicon was flowing gas
to its account while Southland Royalty was not producing and that this created a
gas imbalance. The imbalance was addressed, as between Southland Royalty and
Unicon, by a reduction in the total purchase price for Unicon assets acquired by
Southland Royalty in June 1990. However, there was no payment made to the Trust
at the time of that acquisition.

BROG proposes to address the imbalance with the Trust based upon the terms of a
Gas Balancing Agreement it indicates was in place between Southland Royalty and
Unicon, in connection with the Joint Operating Agreement applicable to the
subject properties. BROG has offered $3,490,000 as a cash settlement. The Trust
is considering the appropriateness of this proposed resolution and this offer
and is consulting with its advisors. No assurance can be given as to when and
how this issue will be resolved or that the gas imbalance issue will be resolved
in favor of the Trust.

CALCULATION OF ROYALTY INCOME:

Royalty income received by the Trust for the three months ended March 31, 2000
and 1999, respectively, was computed as shown in the following table:

<TABLE>
<CAPTION>

                                                  2000              1999
<S>                                             <C>              <C>
Gross proceeds of sales from the
Underlying Properties:

   Gas proceeds                                 $22,513,961      $15,951,226
   Oil proceeds                                     525,410          177,560
                                                -----------      -----------

Total                                            23,039,371       16,128,786
                                                -----------      -----------

Less production costs:
   Severance tax - Gas                            2,194,519        1,648,328
   Severance tax - Oil                               52,040           17,848
   Lease operating expense and property tax       3,107,561        2,795,802
   Capital expenditures                           4,583,126        2,273,201
                                                -----------      -----------

Total                                             9,937,246        6,735,179
                                                -----------      -----------

Net profits                                      13,102,125        9,393,607
Net overriding royalty interest                          75%              75%
                                                -----------      -----------

Subtotal                                          9,826,594        7,045,206
Other (a)                                           250,000
                                                -----------      -----------

Royalty income                                  $10,076,594      $ 7,045,206
                                                ===========      ===========
</TABLE>



(a) Represents an offset to lease operating expense in connection with the
settlement of litigation.


                                     - 11 -

<PAGE>   12

ITEM 3.  QUALITATIVE AND QUANTITATIVE DISCLOSURES ABOUT MARKET RISK

The Trust has not entered into derivative financial instruments, derivative
commodity instruments or other similar instruments during the quarter ended
March 31, 2000. The Trust does not market the Trust gas, oil and/or natural gas
liquids. BROG is responsible for such marketing.



                                     - 12 -

<PAGE>   13

                           PART II - OTHER INFORMATION

ITEM 1.  LEGAL PROCEEDINGS

         The Trust is not a party to any litigation. However, the Trust is aware
         that BROG is involved in litigation from time to time that could affect
         the royalty income received by the Trust.

         A lawsuit was commenced on September 1, 1995 against BROG by certain
         royalty and overriding royalty owners on behalf of those persons
         similarly situated. The suit involves properties that are burdened by
         the Trust. This case is one of six virtually identical class actions
         filed against New Mexico gas producers. All such cases have been
         consolidated in the First Judicial District of Santa Fe County, New
         Mexico where the case is styled San Juan 1990-A, L.P., et al. v. El
         Paso Production Company and Meridian Oil Inc. The plaintiffs allege
         that they and members of the proposed class have been underpaid for
         royalties and overriding royalties. The plaintiffs have sought to
         certify the actions as class actions and seek monetary damages. The
         court has denied class certification, but the plaintiffs have renewed
         their request for class certification. Discovery in this matter is
         closed. BROG anticipates summary judgment proceedings to occur in the
         summer of 2000. Because of the pending nature of the litigation,
         exposure to the Trust from this suit cannot be quantified. However, if
         the plaintiffs who have interests in properties that are burdened by
         the Trust are successful, royalty income received by the Trust could
         decrease.

         In addition, an administrative claim was initiated on March 17, 1997 by
         the Mineral Management Service of the United States Department of the
         Interior (the "MMS") against BROG regarding a gas contract settlement
         dated March 1, 1990, between BROG and certain other parties thereto.
         The claim alleges that additional royalties are due on production from
         federal and Indian leases in the State of New Mexico on properties that
         are burdened by the Royalty. In June 1997 BROG filed its statement of
         reasons thereby contesting whether the royalties are payable as
         claimed. BROG has informed the Trust that the administrative claim is
         in the appeal process. If the MMS claim is successful, royalty income
         received by the Trust could decrease. BROG reports that the MMS and
         BROG have entered into settlement discussions in an attempt to settle
         this issue together with other take-or-pay claims made by the MMS, but
         there has been no indication of the likelihood of success in resolving
         the claim or when the negotiations are to be completed.

         BROG has negotiated with the State of New Mexico for a tax refund based
         upon a claim for reimbursement of compression costs used in calculating
         wellhead values. BROG has obtained the approval of the Attorney General
         of New Mexico of a settlement in the amount of $4,200,000. BROG has
         informed the Trust that its preliminary calculations indicate that the
         proportion of the settlement proceeds which will be attributable to the
         Trust is approximately $250,000.

ITEM 5.  OTHER

         In February 1999, the Trust's internal auditors notified the Trust of
         an apparent gas imbalance. A gas imbalance occurs where more than one
         party is entitled to the economic benefit of the production of natural
         gas, but the gas is sold for the account of less than all of the
         parties. The resulting imbalance may be corrected by various means
         including a cash settlement and/or a volume adjustment whereby an
         increased percentage of future production is sold for the account of
         the underproduced party or parties. The Trust's internal auditors
         suggested that the subject imbalance might relate to the acquisition by
         BROG's predecessor, Southland Royalty Company ("Southland Royalty"), of
         mineral properties which had been operated under a Joint Operating
         Agreement between Southland Royalty and Unicon, the seller of the
         properties. The Trust made inquiry of BROG concerning the imbalance and
         BROG agreed to investigate the records. The Trustee met with BROG
         representatives in June 1999 to discuss the investigation, and by
         correspondence of September 24, 1999, BROG reported that the imbalance
         probably related to problems experienced in the 1980's and early 1990's
         by Southland Royalty and Unicon in



                                     - 13 -
<PAGE>   14

         their dealings with Public Service Company of New Mexico. BROG reported
         that Unicon was flowing gas to its account while Southland Royalty was
         not producing and that this created a gas imbalance. The imbalance was
         addressed, as between Southland Royalty and Unicon, by a reduction in
         the total purchase price for Unicon assets acquired by Southland
         Royalty in June 1990. However, there was no payment made to the Trust
         at the time of that acquisition.

         BROG proposes to address the imbalance with the Trust based upon the
         terms of a Gas Balancing Agreement it indicates was in place between
         Southland Royalty and Unicon, in connection with the Joint Operating
         Agreement applicable to the subject properties and has offered
         $3,490,000 as a cash settlement. The Trust is considering the
         appropriateness of this proposed means of resolution and this offer and
         is consulting with its advisors. No assurance can be given as to when
         and how this issue will be resolved.

Item 6.  Exhibits and Reports on Form 8-K

         (a) Exhibits

             (4)(a) San Juan Basin Royalty Trust Indenture dated November 3,
                    1980, between Southland Royalty Company (now Burlington
                    Resources Oil & Gas Company) and The Fort Worth National
                    Bank (now Bank One, Texas, N.A.), as Trustee, heretofore
                    filed as Exhibit (4)(a) to the Trust's Annual Report on Form
                    10-K to the Securities and Exchange Commission for the
                    fiscal year ended December 31, 1980 is incorporated herein
                    by reference.

             (4)(b) Net Overriding Royalty Conveyance from Southland Royalty
                    Company (now Burlington Resources Oil & Gas Company) to The
                    Fort Worth National Bank (now Bank One, Texas, N.A.), as
                    Trustee, dated November 3, 1980 (without Schedules),
                    heretofore filed as Exhibit (4)(b) to the Trust's Annual
                    Report on Form 10-K to the Securities and Exchange
                    Commission for the fiscal year ended December 31, 1980 is
                    incorporated herein by reference.

             (27)   Financial Data Schedule

         (b) Reports on Form 8-K

             No reports on Form 8-K were filed during the quarter ended March
             31, 2000.



                                     - 14 -
<PAGE>   15

                                   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.

                                           BANK ONE, TEXAS, N.A., AS TRUSTEE FOR
                                           THE SAN JUAN BASIN ROYALTY TRUST



                                           By  /s/   LEE ANN ANDERSON
                                               ----------------------------
                                                     Lee Ann Anderson
                                                      Vice President

Date:  May 15, 2000


               (The Trust has no directors or executive officers.)


                                     - 15 -

<PAGE>   16
                                INDEX TO EXHIBITS
<TABLE>
<CAPTION>


                                                                                          SEQUENTIALLY
               EXHIBIT                                                                       NUMBERED
               NUMBER                        EXHIBIT                                           PAGE

<S>                       <C>
               (4)(a)     San Juan Basin Royalty Trust Indenture dated November
                          3, 1980, between Southland Royalty Company (now
                          Burlington Resources Oil & Gas Company) and The Fort
                          Worth National Bank (now Bank One, Texas, N.A.), as
                          Trustee, heretofore filed as Exhibit (4)(a) to the
                          Trust's Annual Report on Form 10 K to the Securities
                          and Exchange Commission for the fiscal year ended
                          December 31, 1980 is incorporated herein by
                          reference.*


               (4)(b)     Net Overriding Royalty Conveyance from Southland
                          Royalty Company (now Burlington Resources Oil & Gas
                          Company) to The Fort Worth National Bank (now Bank
                          One, Texas, N.A.), as Trustee, dated November 3, 1980
                          (without Schedules), heretofore filed as Exhibit
                          (4)(b) to the Trust's Annual Report on Form 10-K to
                          the Securities and Exchange Commission for the fiscal
                          year ended December 31, 1980 is incorporated herein by
                          reference.*

               (27)      Financial Data Schedule **
</TABLE>


*    A copy of this Exhibit is available to any Unit holder, at the actual cost
     of reproduction, upon written request to the Trustee, Bank One, Texas,
     N.A., P.O. Box 2604, Fort Worth, Texas 76113.

**   Filed herewith.