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                                                                   EXHIBIT 10(a)

                              EMPLOYMENT AGREEMENT


         THIS EMPLOYMENT AGREEMENT ("Agreement") is made and entered into as of
this 27th day of April, 1995, by and among SOUTHSIDE BANCSHARES CORP., a
Missouri corporation (the "Company"), SOUTH SIDE NATIONAL BANK IN ST.
LOUIS, a National Bank (the "Bank") and THOMAS M. TESCHNER ("Employee").

                                    RECITALS

         A. The Company is engaged in the business of a Bank Holding Company
within the meaning of the Bank Holding Company Act of 1956, as amended.

         B. The Bank is engaged in the business of a National Bank.

         C. Each of the Company and the Bank desire to employ Employee as
President and Chief Executive Officer, and Employee desires to be so employed by
the Company and the Bank, all upon the terms set forth herein and, for the
purpose of effecting the same, the Board of Directors of the Company and the
Board of Directors of the Bank have approved this Employment Agreement and
authorized its execution and delivery on the Company's behalf and the Bank's
behalf to the Employee.

         D. The services of the Employee, his experience and knowledge of the
affairs of the Company and the Bank, and his reputation and contacts in the
industry are extremely valuable to the Company and the Bank.

         E. The Company and the Bank consider the establishment and maintenance
of sound and vital management to be a part of each of their overall corporate
strategies and to be essential to protecting and enhancing each of their best
interests and the best interests of each of their subsidiaries, depositors and
shareholders.

                                    AGREEMENT

         To assure each of the Company and the Bank of the Employee's continued
dedication, the availability of his advice and counsel to the Boards of
Directors of the Company and the Bank and the availability of his management
skills to the Company and the Bank, 

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and to induce the Employee to remain and continue in the employ of the Company
and the Bank and for other good and valuable consideration, the receipt and
adequacy whereof each party hereby acknowledges, the Company, the Bank and the
Employee hereby agree as follows:

         1. Employment. The Company agrees to employ Employee as President and
Chief Executive Officer of the Company, the Bank agrees to employ Employee as
President and Chief Executive Officer of the Bank, and Employee agrees to
continue to be so employed during the term of this Agreement, upon the terms and
conditions hereinafter set forth.

         2. Duties. During the term of this Agreement, Employee is to devote
his time, attention and best efforts in carrying out his duties as President and
Chief Executive Officer of the Company and the Bank, which duties include those
as from time to time hereafter may be specified in the Company's and Bank's
By-laws, such other duties as are appropriate for an employee holding a position
of President and Chief Executive Officer in the Company's and the Bank's
businesses, and such other duties as may reasonably be assigned to Employee by
the Company or the Bank. Employee covenants and agrees to diligently and
faithfully serve the Company and the Bank in the capacities set forth above and
to devote such of his professional energies, attention, time, care and best
efforts as is reasonably necessary to the performance of services and the
fulfillment of duties normally associated with the above capacities.

         Nothing in this Section 2 shall be construed as preventing Employee
from investing assets in such form or manner as will not require his services in
the daily operations of the affairs of the companies in which such investments
are made.

         3. Term of Employment. Employment of Employee pursuant to this
Agreement by the Company and the Bank shall commence on the date hereof, and
shall continue for an initial period of three (3) years from such date. Unless
written notice of intent not to renew has been delivered on or before either the
first year anniversary of this Agreement or each successive yearly anniversary
thereafter, the term of Employee's employment pursuant to this Agreement shall
be automatically renewed for a new three (3) year term.

         In the event such notice of intent not to renew is properly delivered,
this Agreement, along with all corresponding rights, duties, and covenants,
automatically shall expire at the end of the 

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initial term or successive term then in progress, subject to the fulfillment of
the continuing rights, duties and obligations as may otherwise be expressly
provided for herein.

         4. Place of Performance. In connection with Employee's employment
hereunder, Employee is to be based at the principal executive offices of the
Company and the Bank, except for required travel in connection with the business
of the Company or the Bank. The Company and the Bank are to furnish Employee
with office space, stenographic and secretarial assistance and such other
facilities and services as are suitable to Employee's position in the Company's
and the Bank's businesses and as are adequate for the performance of his duties
hereunder.

         5. Compensation. As full consideration for all services rendered by
Employee to the Company and the Bank hereunder, the Company and the Bank shall
compensate Employee in the following manner, it being agreed and understood that
such compensation is the total of the sums to be paid or benefits provided by
the Company and the Bank, and in no event shall the Company or the Bank be
required to duplicate any such compensation or benefit which is otherwise
provided by one of them.

            (a) Annual Base Salary. The Company and the Bank shall pay
Employee an initial annual base salary hereunder of $140,000, payable in equal
monthly installments or at such other intervals as may be agreed upon in writing
by the Company, the Bank and Employee. Employee's annual base salary shall be
reviewed at least annually, while this Agreement is in force, to ascertain
whether, in the judgement of the Company's and the Bank's Boards of Directors,
such annual salary should be increased. Notwithstanding the foregoing, in the
event the Company or the Bank approve an annual percentage increase in the
annual salary paid per Company or Bank employee (the "Percentage Increase"),
Employee's annual base salary shall be increased by a percentage which is not to
be less than the greater of the Percentage Increase of the Company or the Bank.
For purposes of this Section, the annual salary paid per Company or Bank
employee is to be computed by dividing (i) the aggregate dollar amount of all
annual base salaries to be paid or previously paid, as the case may be, to the
Company or the Bank employees so entitled (excluding Employee and his annual
base salary), by (ii) the number of such Company or Bank employees, as the case
may be. If Employee's annual base salary is so increased, such salary is not to
be thereafter decreased during the term of this Agreement, and the obligation of
the Company and the Bank 

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hereunder to pay Employee's annual salary thereafter shall relate to such
increased salary.

            (b) Other Benefits. In addition to his annual base salary, Employee 
shall be entitled during the term of this Agreement to:

                (i)      participate in any and all incentive bonus plans of the
Company and the Bank now or hereafter in effect, including without limitation
the Company's Annual Incentive Plan, at a level or levels commensurate with
Employee's position with the Company and the Bank;

                (ii)     participate in any and all employee welfare plans, 
employee benefit plans, stock purchase plans and similar plans of the Company
and the Bank now or hereafter in effect and open to participation by qualifying
employees of the Company and the Bank generally, including accidental death
insurance, group life insurance, group disability insurance, medical and health
plans, sick pay, dental plans, retirement plans, savings plans, cafeteria plans,
supplemental retirement plans, employee stock purchase plans and employee stock
ownership plans; and

                (iii)    enjoy certain personal benefits provided by the Company
and the Bank, including:

                         (A) reimbursement in full of all business, travel and
entertainment expenses reasonably incurred by Employee in performing his duties
hereunder;

                         (B) four (4) weeks of fully paid vacation during each
calendar year at a time or times selected by Employee;

                         (C) those holidays designated by the Company and the
Bank during which the Company's and the Bank's normal business operations are
closed;

                         (D) the use of an automobile, to be replaced every
three (3) years, of such model and type as is befitting the position of
Employee, such use to be provided during the unexpired portion of this
Agreement; and

                         (E) reimbursement of Employee's dues and initiation or
other fees in Greenbriar Hills Country Club, located in St. Louis County,
Missouri and such other professional associations, societies, service
organizations, luncheon clubs and 


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country clubs as are approved by the Company and the Bank.

            (c) Legal Fees. The Company and the Bank agree to reimburse Employee
for any and all legal fees and expenses incurred by Employee in connection with
this Agreement and the transactions contemplated hereby and/or in connection
with any action or proceeding initiated by the Company, the Bank or Employee
with respect to any of the terms and conditions of this Agreement, whether or
not any such action or proceeding is decided favorably to Employee and whether
or not this Agreement has been terminated.

         6. Termination. The employment of Employee hereunder by the Company
and the Bank may be terminated under the circumstances set forth below.

            (a) Termination for Cause. The Company and the Bank may terminate
Employee's employment hereunder for cause. For purposes hereof, "cause" shall
mean: (i) any willful misconduct by Employee resulting in indictment for an
alleged felony; (ii) a violation of any material provision of this Agreement by
Employee; or (iii) any willful failure (other than a failure resulting from
disability or death) by Employee substantially to perform any reasonable
directions of the Company's Board of Directors or the Bank's Board of Directors
(collectively, the "Boards") within sixty (60) days (or such longer period if
more than sixty (60) days are required to substantially perform such directions
with reasonable diligence and Employee has commenced performance within such
sixty (60) days) after written demand for substantial compliance by the Boards,
which written demand is to specifically identify the manner in which the Boards
believe that Employee has not substantially performed. Notwithstanding the
foregoing, the employment of Employee hereunder may not be terminated for cause
unless and until (A) reasonable notice is given to Employee setting forth the
reasons the Company and the Bank intend to terminate Employee's employment, (B)
Employee is provided an opportunity to be heard before the Boards, with counsel,
and (C) after such hearing or opportunity to be heard, written notice of final
termination of employment for cause is delivered to Employee setting forth the
specific reasons therefor and the prospective effective date of such
termination. In addition, termination for cause shall require the affirmative
votes of at least two-thirds of each of the entire Boards (excluding Employee if
Employee is a director). Employee will not be entitled to any further
compensation hereunder for any period subsequent to the effective date of such
termination for cause except for a severance payment (to be paid on the
effective date of such termination) equal to the greater of (1) one-third of


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Employee's then current annual base salary, or (2) a severance payment computed
in accordance with the Company's or the Bank's then existing severance payment
policy. 

            (b) Termination Due to Disability. In the event of Employee's
disability, the Company and the Bank shall continue to make payments to Employee
hereunder for a period of six (6) months subsequent to such disability. If, at
the end of such six (6) month period, Employee remains disabled, the Company and
the Bank may terminate Employee's employment hereunder upon thirty (30) days'
written notice to Employee setting forth the prospective effective date of such
termination. Such termination due to disability shall require the affirmative
votes of at least two-thirds of each of the entire Boards (excluding Employee if
Employee is a director). During any period of disability and prior to the
effective date of any termination due to disability, Employee shall continue to
receive the compensation payable to him hereunder. On the effective date of such
termination due to disability, the Company and the Bank shall pay Employee a
severance payment equal to the greater of (i) one-third of Employee's then
current annual base salary, or (ii) a severance payment computed in accordance
with the Company's and the Bank's then existing severance payment policy.
Employee shall not be entitled to any additional compensation from the Company
or the Bank for any period subsequent to the effective date of such termination
except for payments to Employee under the Company's or the Bank's disability
benefit plans (the "Disability Plans"). Notwithstanding the foregoing, in the
event the Disability Plans in force as of the date of this Agreement (the
"Current Disability Plans") are amended and such amendment or amendments reduce
or terminate benefits payable to Employee thereunder, the Company and the Bank
shall pay Employee an amount equal to the difference between (A) the amount of
benefits Employee would have been entitled to receive under the Current
Disability Plans after the effective date of such termination, and (B) the
amount of benefits Employee is actually paid under the Disability Plans after
the effective date of such termination. For purposes hereof, "disability" and
"disabled" shall mean the inability of Employee to perform his duties hereunder
due to illness or injury as determined by a physician acceptable to the Company,
the Bank and Employee.

            (c) Termination Due to Death. In the event of the death of
Employee during the Term of employment hereunder, the Company and the Bank shall
pay to Employee's designated beneficiary, or if no beneficiary has been
designated, to Employee's estate, no later than thirty (30) days following the
date of Employee's death, the 


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benefits payable under the Company's and the Bank's accidental death, life
insurance and similar plans for employees (the "Death Benefit Plans"). In the
event the Death Benefit Plans in force as of the date of this Agreement (the
"Current Death Benefit Plans") are amended and such amendment or amendments
reduce or terminate benefits payable to Employee or his beneficiaries
thereunder, the Company and the Bank shall pay Employee's designated
beneficiary, or if no beneficiary has been designated, Employee's estate, within
ninety (90) days after the date of Employee's death, a lump sum amount equal to
the difference between (i) the aggregate sum which would have been payable to
Employee or his beneficiaries under the Current Death Benefit Plans, and (ii)
the aggregate sum which is payable to Employee or his beneficiaries under the
Death Benefit Plans. The obligations of the Company and the Bank to pay Employee
additional compensation hereunder shall terminate at such time as the Company
and the Bank shall fully comply with their obligations under this Section 6(c).

            (d) Breach by the Company or the Bank. In the event the Company or
the Bank breaches any material provision of this Agreement and such breach is
not cured within ten (10) days after delivery of written notice thereof to the
Company or the Bank by Employee, identifying the breach with reasonable
particularity, Employee may at his sole option, in addition to any other remedy
available to him, cease to perform his duties hereunder and terminate this
Agreement and his employment with the Company and the Bank. In such event, any
and all amounts payable to Employee hereunder shall become immediately due and
payable, and Employee shall have no obligation to mitigate.

            (e) Continuation of Health Benefits After Termination.
Notwithstanding anything to the contrary herein, the Company and the Bank shall
provide Employee with a continuation of the welfare benefits of health and
medical insurance for three (3) full years from the effective date of any
termination of Employee's employment hereunder (other than a termination due to
death) at the sole cost and expense of the Company and the Bank. These benefits
shall be provided to Employee at the same coverage level as in effect as of
Employee's effective date of termination. These welfare benefits shall be
discontinued prior to the end of the three (3) year period in the event Employee
has available substantially similar benefits from a subsequent employer, as
determined by the Boards.

         7. Change in Control.


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            (a) Employment Terminations in Connection with a Change in Control.
In the event of a Qualifying Termination (as defined below) within six (6) full
calendar months prior to the effective date of a Change in Control of the
Company and/or the Bank, or within three (3) years following the effective date
of a Change in Control, then in lieu of all other benefits provided to Employee
under the provisions of this Agreement, the Company and the Bank shall pay to
Employee and provide him with the following severance benefits:

                (1) An Amount equal to three (3) times the highest rate of
Employee's annual base salary rate in effect at any time during the term of this
Agreement up to and including the effective date of termination;

                (2) An Amount equal to three (3) times the highest annual bonus
of Employee prior to the effective date of termination;

                (3) An amount equal to Employee's unpaid annual salary and
accrued vacation pay through the effective date of termination; and

                (4) A continuation of the welfare benefits of health and medical
insurance for three (3) full years from the effective date of termination at the
sole cost and expense of the Company and the Bank. These benefits shall be
provided to Employee at the same coverage level as in effect as of Employee's
effective date of termination. These welfare benefits shall be discontinued
prior to the end of the three (3) year period in the event Employee has
available substantially similar benefits from a subsequent employer, as
determined by the Boards.

         For purposes of this Section 7, a Qualifying Termination shall mean any
termination of Employee's employment hereunder OTHER THAN: (1) by the Company
and the Bank for Cause (as provided in Section 6(a) hereof); or (2) by reason of
Employee's death (as provided in Section 6(c) hereof) or disability (as provided
in Section 6(d) hereof). Notwithstanding anything to the contrary herein,
Employee may voluntarily terminate his employment hereunder at any time for any
reason whatsoever within the period beginning on the effective date of a Change
in Control and ending six (6) months thereafter and such voluntary termination
shall be a Qualifying Termination for purposes of this Section 7 and Employee
shall thereupon receive the payments and other benefits set forth in this
Section 7.




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            (b) Definition of "Change in Control". A Change in Control of the
Company and/or the Bank shall be deemed to have occurred as of the first day any
one or more of the following conditions shall have been satisfied:

                (1) Any individual, corporation (other than the Company),
partnership, trust, association, pool, syndicate, or any other entity or any
group of persons (other the Southside Bancshares Corp. 1993 Non-Qualified
Employee Stock Ownership Plan) acting in concert becomes the beneficial owner,
as that concept is defined in Rule 13d-3 promulgated by the Securities and
Exchange Commission under the Securities Exchange Act of 1934, as amended, of
the securities of the Company and/or the Bank possessing twenty-five percent
(25%) or more of the voting power for the election of directors of the Company
and/or the Bank;'

                (2) There shall be consummated any consolidation, merger or
other business combination involving the Company and/or the Bank or the
securities of the Company and/or the Bank in which holders of voting securities
of the Company and/or the Bank, as the case may be, immediately prior to such
consummation own, as a group, immediately after such consummation, voting
securities of the Company and/or the Bank, as the case may be (or if the Company
or the Bank does not survive such transaction(s), voting securities of the
corporation(s) surviving such transaction(s)) having less than fifty percent
(50%) of the total voting power in an election of directors of the Company
and/or the Bank (or such other surviving corporation(s));

                (3) During any period of two (2) consecutive years, individuals
who at the beginning of such period constitute the directors of the Company
and/or the Bank cease for any reason to constitute at least a majority thereof;

                (4) Removal by the stockholders of the Company and/or the Bank
of all or a majority of the incumbent directors of the Company or the Bank,
respectively, other than a removal for Cause; or

                (5) There shall be consummated any sale, lease, exchange, or
other transfer (in one transaction or a series of related transactions) of all,
or substantially all, of the assets of the Company and/or the Bank (on a
consolidated basis) to a party which is not controlled by or under common
control with the Company and/or the Bank, as the case may be.


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                (c) Limitation on Change in Control Benefits. Notwithstanding
any other provision of this Agreement, if any portion of the benefits provided
in Section 7(a) herein (the "Benefits") or any other payment under this
Agreement, or under any other agreement with or plan of the Company (in the
aggregate, the "Total Payments") would constitute an "excess parachute payment"
as defined and valued in Section 280G(b) of the Internal Revenue Code of 1986,
as amended (the "Code"), then the payments to be made to Employee under this
Agreement shall be reduced such that the value of the aggregate Total Payments
that Employee is entitled to receive shall be one dollar ($1.00) less than the
maximum amount which Employee may receive without becoming subject to the tax
imposed by Section 49999 of the Code, or which the Company and/or the Bank may
pay without loss of deduction under Section 280G(a) of the Code.

         Within sixty (60) days following delivery of the notice of employment
termination by Employee or the Company and the Bank pursuant to the terms of
this Agreement, or notice by the Company and the Bank to Employee of their
belief that there is a payment or benefit due Employee which will result in an
"excess parachute payment" as defined in Section 280G(b) of the Code, Employee,
the Company and the Bank, at the Company's and the Bank's expense, shall obtain
the opinion of such legal counsel, which need may not be unqualified, as
Employee may choose, which sets forth: (i) the amount of Employee's "annualized
includible compensation for the base period" (as defined in Code Section
280G(d)(1)); (ii) the present value of the Total Payments; and (iii) the amount
and present value of any "excess parachute payment." The opinion of such legal
counsel shall be supported by the opinion of a certified public accounting firm.
Such opinion shall be binding upon the Company, the Bank and Employee.

         In the event that such opinion determines that there would be an
"excess parachute payment," the benefits provided in Section 7(a) herein, or any
other payment determined by such counsel to be includible in the Total Payments
shall be reduced or eliminated as specified by Employee in writing delivered to
the Company and the Bank within thirty (30) days of Employee's receipt of such
opinion, or, if Employee fails to so notify the Company and the Bank, then as
the Company and the Bank shall reasonably determine so that under the basis of
calculations set forth in such opinion there will be no "excess parachute
payment."

         The provisions of this Section 7(c), including the calculations,
notices and opinion provided for herein shall be 

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based upon the conclusive presumption that: (i) the compensation and benefits
provided for in Section 7(a) herein, and (ii) any other compensation earned
prior to the effective date of employment termination by Employee pursuant to
the Company's and the Bank's compensation programs (if such payments would have
been made in the future in any event, even though the timing of such payment is
triggered by the Change in Control), are reasonable.

                (d) Subsequent Imposition of Excise Tax. If, notwithstanding
compliance with the provisions of Section 7(c) herein, it is ultimately
determined by a court or pursuant to a final determination by the Internal
revenue Service that any portion of the Total Payments is considered to be a
"parachute payment" subject to the excise tax under Section 4999 of the Code,
which was not contemplated to be a "parachute payment" at the time of payment
(so as to accurately determine whether a limitation should have been applied to
the Total Payments to maximize the net benefit to Employee, as provided in
Section 7(c) hereof), Employee shall be entitled to receive a lump sum cash
payment sufficient to place Employee in the same net after-tax position,
computed by using the "Special Tax Rate" as such term is defined below, that
Employee would have been in had such payment not been subject to such excise
tax, and had Employee not incurred any interest charges or penalties with
respect to the imposition of such excise tax. For purposes of this Agreement,
the "Special Tax Rate" shall be the highest effective federal and state marginal
tax rates applicable to Employee in the year in which the payment contemplated
under this Section 7(d) is made.

         8. Noncompete. In the event Employee is terminated for cause or
Employee improperly terminates his own employment hereunder, during the period
beginning on the date of such termination of Employee's employment and
continuing for six (6) months after such date, Employee may not, without the
prior written approval of the Board, either individually or with or through an
Affiliate of Employee, contact or solicit any customers, depositors or clients
of the Company, the Bank or any of their subsidiaries.

         9. Confidential Information.

            (a) Immediately upon Employee's termination of employment, Employee
is to deliver to the president of the Company, the Bank or to the Boards all
materials and things relating to Employee's employment by the Company and the
Bank, including any and all materials and things embodying any of the
confidential information described in Section 8(b). Employee may neither retain


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any copies or reproductions thereof nor deliver any such materials and things or
copies or reproductions thereof to any third person.

            (b) Employee acknowledges that, in the course of his employment with
the Company and the Bank, he will become acquainted with confidential and
proprietary information of the Company and the Bank. Employee agrees that he
will not, without the prior written consent of the Company and the Bank,
disclose or make any use of such confidential or proprietary information except
in the ordinary course of his employment with the Company and the Bank or except
as may be requested by the Company and the Bank or otherwise be required by
applicable law.

         10. Dissemination of Information. During the term of his employment
with the Company and the Bank, and for a period of five (5) years thereafter,
Employee will not disclose or otherwise provide information or documents (other
than in the ordinary course of employment with the Company and the Bank) to any
person regarding the Company or the Bank (a) without the prior written consent
of the Company and the Bank, (b) except to regulatory officials having
jurisdiction over Employee, or (c) except as required by law or legal process or
in connection with any legal proceeding to which he is a party or is otherwise
subject. In any event, Employee will immediately notify the Boards of any and
all requests or demands for such information or documents. This Section applies
to all information and documents regarding the Company and the Bank, whether or
not the same is confidential.

         11. Construction. Unless the context of this Agreement clearly requires
otherwise, references to the plural include the singular and vice versa,
references to one gender include all genders, "including" is not limiting, and
"or" has the inclusive meaning represented by the phrase "and/or". The words
"hereof," "herein," "hereby," "hereunder," and similar terms in this Agreement
refer to this Agreement as a whole and not to any particular provision of this
Agreement. Article, section and subsection references are to this Agreement
unless otherwise specified.

         12. Amendment and Modification. No amendment, modification, supplement,
termination, consent or waiver of any provision of this Agreement, nor consent
to any departure herefrom, will in any event be effective unless the same is in
writing and is signed by the party against whom enforcement of the same is
sought. Any waiver of any provision of this Agreement and any consent to any
departure from the terms of any provision of this Agreement is to be 


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<PAGE>   13

effective only in the specific instance and for the specific purpose for which
given.

         13. Approvals and Consents. If any provision hereof requires the
approval or consent of any party to any act or omission, such approval or
consent is not to be unreasonably withheld or delayed except as set forth
herein.

         14. Assignments. No party may assign or transfer any of its rights or
obligations under this Agreement to any other person without the prior written
consent of the other parties.

         15. Captions. Captions contained in this Agreement have been inserted
herein only as a matter of convenience and in no way define, limit, extend or
describe the scope of this Agreement or the intent of any provision hereof.

         16. Compliance with Law. None of the terms or provisions of this
Agreement require any of the parties to take any action prohibited by, or
contrary to, applicable law.

         17. Counterparts. This Agreement may be executed by the parties on any
number of separate counterparts, and all such counterparts so executed
constitute one agreement binding on all the parties notwithstanding that all the
parties are not signatories to the same counterpart.

         18. Entire Agreement. This Agreement constitutes the entire agreement
among the parties pertaining to the subject matter hereof and supersedes all
prior agreements, letters of intent, understandings, negotiations and
discussions of the parties, whether oral or written.

         19. Failure or Delay. No failure on the part of any party to exercise,
and no delay in exercising, any right, power or privilege hereunder operates as
a waiver thereof; nor does any single or partial exercise of any right, power or
privilege hereunder preclude any other or further exercise thereof, or the
exercise of any other right, power or privilege. No notice to or demand on any
party in any case entitles such party to any other or further notice or demand
in similar or other circumstances.

         20. Further Assurances. The parties will execute and deliver such
further instruments and do such further acts and things as may be required to
carry out the intent and purpose of this Agreement.


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<PAGE>   14

         21. Governing Law. This Agreement and the rights and obligations of the
parties hereunder are to be governed by and construed and interpreted in
accordance with the laws of the State of Missouri applicable to contracts made
and to be performed wholly within Missouri, without regard to choice or conflict
of laws rules.

         22. No Joint Venture or Partnership. The parties agree that nothing
contained herein is to be construed as making the parties joint venturers or
partners.

         23. Notices. All notices, consents, requests, demands and other
communications hereunder are to be in writing, and are deemed to have been duly
given or made: (a) when delivered in person, (b) three days after deposited in
the United States mail, first class postage prepaid, (c) in the case of
telegraph or overnight courier services, one business day after delivery to the
telegraph company or overnight courier service with payment provided for, or (d)
in the case of telex or telecopy, when sent, verification received, in each case
addressed as follows:

         (i)    If to the Employee:      His last known address shown on the 
                                         Records of the Company and the Bank.

         (ii)   If to the Company:       Southside Bancshares Corp.
                                         Attention:  Corporate Secretary
                                         3606 Gravois Avenue
                                         St. Louis, Missouri  63116

         (iii)  If to the Bank:          South Side National Bank 
                                         Attention:  Cashier
                                         3606 Gravois Avenue
                                         St. Louis, Missouri  63116


or to such other address as any party may designate by notice to the other
parties in accordance with the terms of this Section.

         24. Publicity. Any publicity release, advertisement, filing, public
statement or announcement made by or at the request of any party regarding this
Agreement is to be first reviewed by and must be satisfactory to the other
parties.

         25. Remedies Cumulative. Each and every right granted hereunder and the
remedies provided for under this Agreement are 


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<PAGE>   15

cumulative and are not exclusive of any remedies or rights that may be available
to any party at law, in equity, or otherwise.

         26. Severability. Any provision of this Agreement which is prohibited,
unenforceable or not authorized in any jurisdiction is, as to such jurisdiction,
ineffective to the extent of any such prohibition, unenforceability or
nonauthorization without invalidating the remaining provisions hereof, or
affecting the validity, enforceability or legality of such provision in any
other jurisdiction, unless the ineffectiveness of such provision would result in
such a material change as to cause completion of the transactions contemplated
hereby to be unreasonable.

         27. Specific Performance and Injunctive Relief. Each party recognizes
that, if it fails to perform, observe or discharge any of its obligations under
this Agreement, no remedy at law will provide adequate relief to the other
parties. Therefore, each party is hereby authorized to demand specific
performance of this Agreement, and is entitled to temporary and permanent
injunctive relief, in a court of competent jurisdiction at any time when any
other party fails to comply with any of the provisions of this Agreement
applicable to it. To the extent permitted by Applicable Law, each party hereby
irrevocably waives any defense that it might have based on the adequacy of a
remedy at law which might be asserted as a bar to such remedy of specific
performance or injunctive relief.

         28. SUBMISSION TO JURISDICTION. ANY LEGAL ACTION OR PROCEEDING WITH
RESPECT TO THIS AGREEMENT OR ANY DOCUMENT RELATED HERETO MAY BE BROUGHT IN THE
COURTS OF THE STATE OF MISSOURI OR ANY COURT OF THE UNITED STATES OF AMERICA FOR
THE EASTERN DISTRICT OF MISSOURI, AND, BY EXECUTION AND DELIVERY OF THIS
AGREEMENT, EACH PARTY HEREBY ACCEPTS FOR ITSELF AND IN RESPECT OF ITS PROPERTY,
GENERALLY AND UNCONDITIONALLY, THE JURISDICTION OF SUCH COURTS. THE PARTIES
IRREVOCABLY WAIVE ANY OBJECTION, INCLUDING ANY OBJECTION TO THE LAYING OF VENUE
OR BASED ON THE GROUNDS OF FORUM NON CONVENIENS, WHICH ANY OF THEM MAY NOW OR
HEREAFTER HAVE TO THE BRINGING OF ANY SUCH ACTION OR PROCEEDING IN SUCH
RESPECTIVE JURISDICTIONS. EACH PARTY IRREVOCABLY CONSENTS TO THE SERVICE OF
PROCESS OF ANY OF SUCH COURTS IN ANY SUCH ACTION OR PROCEEDING BY THE MAILING OF
COPIES THEREOF BY REGISTERED OR CERTIFIED MAIL, POSTAGE PREPAID, TO EACH OF THE
OTHER PARTIES AT ITS ADDRESS PROVIDED HEREIN, SUCH SERVICE TO BECOME EFFECTIVE
30 DAYS AFTER SUCH MAILING.



                                       15

<PAGE>   16

         29. Successors and Assigns. All provisions of this Agreement are
binding upon, inure to the benefit of, and are enforceable by or against, the
parties and their respective heirs, executors, administrators or other legal
representatives and permitted successors and assigns.

         30. Third-Party Beneficiary. This Agreement is solely for the benefit
of the parties and their respective successors and permitted assigns, and no
other person has any right, benefit, priority or interest under, or because of
the existence of, this Agreement.

         31. Waiver of Jury Trial. Each party waives the right to a trial by
jury.





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                                       16

<PAGE>   17


         32. Signatory Warranty. Each party executing this Agreement warrants
that he is authorized to do so on behalf of the party for whom he signs this
Agreement.

                                         SOUTHSIDE BANCSHARES CORP.


                                         By:   /s/ Howard F. Etling
                                            -------------------------------- 

                                         SOUTH SIDE NATIONAL BANK


                                         By:   /s/ Howard F. Etling
                                            -------------------------------- 

                                         Employee


                                         By:   /s/ Thomas M. Teschner
                                            -------------------------------- 






                                       17
<PAGE>   18
                        AMENDMENT TO EMPLOYMENT AGREEMENT


         This Amendment to Employment Agreement (this "Amendment") is made and
entered into this 1st day of April, 1997, by and among SOUTHSIDE BANCSHARES,
INC., a Missouri corporation (the "Company"), SOUTH SIDE NATIONAL BANK IN ST.
LOUIS, a National Bank (the "Bank") and THOMAS M. TESCHNER ("Employee").

                                    RECITALS

         WHEREAS, the Company, the Bank and Employee are parties to that certain
Employment Agreement dated April 27, 1995 (the "Agreement"); and

         WHEREAS, the parties wish to amend the Agreement as set forth herein;

         NOW, THEREFORE, in consideration of the covenants and agreements
contained herein, the parties agree as follows:

         1.   Ratification of Agreement. The terms of the Agreement are hereby
ratified and confirmed in their entirety subject to the amendments made herein.

         2.   Section 7(a). The last sentence of subsection (a) of Section 7 of
the Agreement is deleted in its entirety and is hereby replaced with the
following:

         Notwithstanding anything to the contrary herein, Employee may
         voluntarily terminate his employment hereunder at any time for any
         reason whatsoever within the period beginning on the effective date of
         a Change in Control and ending two (2) years thereafter and such
         voluntary termination shall be a Qualifying Termination for purposes of
         this Section 7 and Employee shall thereupon receive the payments and
         other benefits set forth in this Section 7.

         3.   Section 7(c). Subsection (c) of Section 7 of the Agreement is
deleted in its entirety and is hereby replaced with the following:

              (c) Payment of Excise Tax. Within sixty (60) days following
         delivery of the notice of employment termination by Employee or the
         Company and the Bank pursuant to the terms of this Agreement, or notice
         by Employee of his belief that there is a payment or benefit due
         Employee which will result in an "excess parachute payment" as defined
         in Section 280G(b) of the Internal Revenue Code of 1986, as amended
         (the "Code"), Employee, the Company and the Bank, at the Company's and
         the Bank's expense, shall obtain the opinion of the Company's legal
         counsel, which need may not be unqualified, which sets forth: (i) the


<PAGE>   19

         amount of Employee's "annualized includible compensation for the base
         period" (as defined in Code Section 280G(d)(1)); (ii) the present value
         of the benefits provided in Section 7(a) herein or any other payment
         under this Agreement, or under any other agreement with or plan of the
         Company (in the aggregate, the "Total Payments"); and (iii) the amount
         and present value of any "excess parachute payment;" and (iv) the
         amount and present value of the excise tax on any such "excess
         parachute payment." The opinion of such legal counsel shall be
         supported by the opinion of a certified public accounting firm. Such
         opinion shall be binding upon the Company, the Bank and Employee.

         If it is determined by the Company's legal counsel that any portion of
         the Total Payments constitutes a "parachute payment" subject to the
         excise tax of Section 4999 of the Code, Employee shall be entitled to
         receive from the Company and the Bank a lump sum cash payment
         sufficient to place Employee in the same net after tax position that
         Employee would have been in had such payment not been subject to such
         excise tax.

         The provisions of this Section 7(c), including the calculations,
         notices and opinion provided for herein shall be based upon the
         conclusive presumption that: (i) the compensation and benefits provided
         for in Section 7(a) herein, and (ii) any other compensation earned
         prior to the effective date of employment termination by Employee
         pursuant to the Company's and the Bank's compensation programs,
         including, without limitation, the Company's 1993 Non-Qualified Stock
         Option Plan (if such payments would have been made in the future in any
         event, even though the timing of such payment is triggered by the
         Change in Control), are reasonable.

         Section 7(d). Subsection (d) of Section 7 of the Agreement is deleted
         in its entirety and is hereby replaced with the following:

             (d) Subsequent Imposition of Excise Tax. If it is ultimately
         determined by a court or pursuant to a final determination by the
         Internal Revenue Service, that the amount of Total Payments
         constituting a "parachute payment" subject to the Excise Tax of Section
         4999 of the Code is greater than the amount so determined by legal
         counsel pursuant to Section 7(c) herein, Employee shall be entitled to
         receive an additional lump sum cash payment sufficient to place
         Employee in the same net after tax position that Employee would have
         been in had such payment not been subject to such excise tax and had
         Employee not incurred any interest or penalties with respect to the
         imposition of such excise tax.


                                       2

<PAGE>   20


         4.   Section 7(f). The following provision is hereby added as a 
separate subsection (f) to Section 7 of the Agreement:

              (f) Other Benefits Upon Termination. On the effective date of
         any termination of Employee's employment hereunder (other than a
         termination for cause or due to death), (i) the Company and the Bank
         shall transfer title to Employee's membership in Greenbriar Hills
         Country Club to Employee; and (ii) Employee shall receive the title to
         the automobile then being provided to him in accordance with Section
         5(b)(iii)(D).

         5.   Effect of Amendment. In the event of any conflict or inconsistency
between the terms and conditions of this Amendment and the Agreement, the terms
and conditions of this Amendment shall control. Except as provided in this
Amendment, the terms and conditions of the Agreement shall remain unchanged and
in full force and effect.

         6.   Counterparts. This Amendment may be executed by the parties on any
number of separate counterparts, and all such counterparts so executed
constitute one agreement binding on all the parties notwithstanding that all the
parties are not signatories to the same counterpart.

         6.   Governing Law. This Amendment and the rights and obligations of 
the parties hereunder are to be governed by and construed and interpreted in
accordance with the laws of the State of Missouri applicable to contracts made
and to be performed wholly within Missouri, without regard to choice or conflict
of laws rules.

                  [remainder of page intentionally left blank]



                                       3

<PAGE>   21


         IN WITNESS WHEREOF, the parties have executed this Amendment on the
date and year first above written.


                                    SOUTHSIDE BANCSHARES CORP.


                                    By:   /s/ Howard F. Etling
                                       --------------------------------------

                                    Name:  Howard F. Etling
                                         ------------------------------------

                                    SOUTH SIDE NATIONAL BANK


                                    By:   /s/ Howard F. Etling
                                       --------------------------------------

                                    Name:  Howard F. Etling
                                         ------------------------------------

                                    EMPLOYEE


                                    By:   /s/ Thomas M. Teschner
                                       --------------------------------------


                                       4