[Graphic omitted]   Electronic
                    Sensor Technology

May 16, 2005

Mr. Matthew Collier
115 Via Sandra
Thousand Oaks, CA 91320

Dear Matthew:

RE:  OFFER LETTER OF EMPLOYMENT

Electronic Sensor Technology (the "Company" and "EST") is pleased to confirm
your employment on the following terms:

     1.   POSITION. You will serve in the full time position of President and
          Chief Executive Officer reporting to the Chairman and responsible to
          the Board of Directors of the Company. You will also be nominated to
          serve on the Board subject to the Board's approval. The Chairman shall
          monitor and review your performance and have the ability to terminate
          your employment. Your employment shall commence upon the execution of
          this Agreement.

     2.   CASH COMPENSATION. The Company will pay you a salary at the rate of $
          220,000 per year, payable in accordance with the Company's standard
          payroll schedule. This salary will be subject to adjustment pursuant
          to the Company's employee compensation policies in effect from time to
          time but no escalation is guaranteed. The Company believes in pay-for
          performance and, as such, we offer you a potential target bonus of 25%
          of your annual salary based on the Company's success in improving
          sales, orders, and operating income, and launching strategic
          initiatives that the Board believes position the company well for the
          future. The Board will perform the necessary evaluation and pay this
          bonus, totally at its discretion, at the end of the first year of
          employment.

     3.   EQUITY-BASED COMPENSATION. Subject to approval by the Company's Board
          of Directors, you will receive a grant of, 75,000 shares of restricted
          stock that can be traded one year from the date of employment, and
          another 75,000 shares will be granted one year from the date of
          employment, if still employed by the company, tradable one year from
          issue on the anniversary date of your employment. In addition, you
          will receive a grant of 500,000 shares of stock options, 33% of which
          vest one year after the date of employment, 33% on the second
          anniversary date of employment , and 34% at the third anniversary date
          of employment . The strike price will be equal to the market value on
          the date this employment contract is signed. Commencing immediately
          after your date of hire, the Options will be subject to the terms and
          conditions of the applicable stock option agreement.

     4.   EMPLOYEE BENEFITS. As a regular employee of the Company, you will be
          eligible to participate in a number of Company-sponsored benefits
          including paid vacation, all in accordance with the Company's policies
          as in effect from time to time. In addition, you will be covered under

<PAGE>

          the Company's health, 401(K) and group insurance programs. In
          accordance with the Company's generally applicable policies, you will
          be reimbursed for all reasonable travel and business expenses incurred
          by you in connection with your employment duties.

     5.   ASSIGNMENT OF RIGHTS, NON-SOLICITATION, CONFIDENTIALITY AND
          NON-DISCLOSURE AGREEMENT. You agree to execute the Assignment of
          Rights, Non-Solicitation of Employees and Vendors, Confidentiality and
          Non-Disclosure Agreements as shall be provided to you by the Company.

     6.   TERMINATION: Employment may be terminated by the Company: (i) for
          cause, as defined, in which case the employee shall be entitled to
          receive only his base salary through the date of termination; (ii)
          without cause, in which case the employee shall be entitled to receive
          (a) continuation of his base salary for six months, (b) any bonus
          earned and/or accrued through the date of termination, and (c) six
          month acceleration of the unvested stock options; or (c) upon the
          death or long-term disability of the employee.

     7.   INDEMNIFICATION. To the fullest extent permitted by the Company's
          charter documents and applicable law, the Company agrees to defend and
          indemnify you and hold you harmless against any liability that you
          incur within the scope of your employment with the Company. The
          Company agrees to use its best efforts to purchase and maintain
          adequate Directors' and Officers' liability insurance.

     8.   EMPLOYMENT RELATIONSHIP. Your employment with the Company continues to
          be for no specific period of time. Your employment with the Company
          will continue to be "at will," meaning that either you or the Company
          may terminate your employment at any time and for any reason, with or
          without cause. Any contrary representations that may have been made to
          you are superseded by this letter agreement. This is the full and
          complete agreement between you and the Company on this term.

     9.   OUTSIDE ACTIVITIES. While you render services to the Company, you
          agree that you will not engage in any other employment, consulting or
          other business activity without the prior written consent of the
          Company, which consent shall not be unreasonably withheld. While you
          render services to the Company, you also will not assist any person or
          entity in competing with the Company, in preparing to compete with the
          Company or in hiring any employees or consultants of the Company.

     10.  WITHHOLDING TAXES. All forms of compensation referred to in this
          letter agreement are subject to reduction to reflect applicable
          withholding and payroll taxes and other deductions required by law.

     11.  ENTIRE AGREEMENT. Except as set forth herein, this letter agreement
          supersedes and replaces any prior agreements, representations or
          understandings, whether written, oral or implied, between you and the
          Company.

     12.  Your continued employment with EST is expressly contingent upon EST
          receiving, within seven (7) of your first day, the following:

          a.   Acceptable results from a background investigation. Any
               falsification of employment history or educational background
               will result in withdrawal of the offer and/or termination of
               employment.
          b.   Signed copies of the EST (i) Employee Agreement, (ii)
               Confidentiality Guidelines, and (iii) Code of Conduct, stating,
               among other things, that you will keep confidential company
               information throughout and beyond your employment with EST.
          c.   Satisfactory proof of identification and work authorization as
               required by the Immigration Reform and Control Act of 1990.

          Failure to execute the documents outlined above will be considered
          termination for cause.
<PAGE>

We hope that you will find the above terms acceptable. You may indicate your
agreement with these terms by signing and dating the enclosed letter agreement
and returning it to me. By signing this letter agreement, you reconfirm to the
Company that you have no contractual commitments or other legal obligations that
would prohibit you from performing your duties for the Company.

This offer of employment is open until Monday May 23rd, 2005 at 5:00 PM (Pacific
Time).

Let me close by reaffirming our belief that the skills and background you bring
to EST will be instrumental to the future success of the Company. Matt, I look
forward to working with you as CEO of EST.

Very truly yours,


/s/ Jim Frey
-------------------------------------
Jim Frey
Chairman

Electronic Sensor Technology, Inc.

I have read and accept and agree to the above terms of employment:


/s/ Matthew Collier
-------------------------------------
Matthew Collier

May 16, 2005
-------------------------------------
Dated