This article describes the optical power control module, of laser diodes, which is included in the therapy installation using local hyperthermia. The function of this module is to produce and maintain, during the entire duration of the therapy procedure, the stable optical power, which has an enormous significance in efficiency of therapy using local hyperthermia. Also the module obligations are: monitoring the laser diodes performance, which also plays an important role in proper functioning of the entire system. This module can serve up to four laser diodes simultaneously, is equipped with RS232 serial interface, necessary to control module via computer. For this purpose, was prepared a computer program that allows the operator to install optical power level for each of the four laser diodes and to monitor laser diodes efficiency. The main element of this module is the microcontroller ATmega16, equipped with a periphery, corresponding the requirements of given module