FLIPRTETRA. This product is the fourth generation FLIPR instrument. It combines all of the benefits of preceding versions of FLIPR with new capabilities in a completely redesigned, compact platform. FLIPRTETRA features simultaneous liquid transfer of samples in 96, 384 and 1,536 well microplates, allowing customers to screen as many as 250,000 samples daily with little human intervention. In addition, the instrument reads multiple wavelengths, enabling a broader set of applications, and incorporates interfaces that allow it to integrate into automated screening lines

EXHIBIT 10.46

August 25, 2003

Jan Hughes
2027 Mezes Avenue
Belmont, CA 94002

Dear Jan:

Molecular Devices Corporation is pleased to confirm our verbal offer for the salaried, exempt position of Director, IonWorks Product Development. In this position you will report to John Senaldi. This offer is contingent upon the successful completion of professional references and background check.

Your base salary will be $10,833.33 per month ($130,000.00 per annum) payable semi-monthly on the 15th and last day of each month. You will also receive all the employment benefits available to regular full-time employees of Molecular Devices Corporation.

You will be eligible to receive 5,000 Incentive Stock Options subject to the approval of the Molecular Devices Board of Directors. These options will vest in accordance with the Company’s vesting schedule over a period of four (4) years, and will be subject to the provisions of the Company’s 1995 Stock Option Plan as amended.

Upon your start date, as a condition of employment, you will be required to sign an Employee Confidentiality and Inventions Agreement (copy of agreement attached). Please review this agreement carefully; if you have any questions regarding this agreement, please feel free to call me.

This offer is made contingent upon your ability to provide proof of identification and authorization to work in the United States. Upon employment at Molecular Devices, you will be required to furnish such documentation as described in the enclosed materials.

Additionally, this written offer constitutes all conditions and agreements of Molecular Devices Corporation. Upon acceptance of this offer, please sign, date, indicate your start date, and return this letter and the enclosed Application Form to the Human Resources Department. However, if you have not responded to this offer within five (5) days of receipt the offer will be withdrawn.

Jan, Molecular Devices Corporation is facing many exciting challenges as we continue to grow. Your experience and talents will be strong additions to our company. We are looking forward to having you join our team.

Sincerely,

MOLECULAR DEVICES CORPORATION

/s/ Patricia Sharp

Patricia Sharp
VP Human Resources

PS/ks

Attachments

Date: 8/27/03
Start Date: 9/15/03