The influence of red laser irradiation on the growth of colonies of Staphylococcus aureus and photodynamic effect of the photosensi- tizer Photoditazin were performed. It is established that the radiation of a semiconductor red laser (? = 660 nm, 100 mW/cm2.) has a direct bacteriostatic effect on the growth of S. aureus. This effect on the standard strain is manifested only when relatively high doses are used (180 J/cm2). Inhibition of bacterial growth reaches 36%.