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%. Photosensitivity of the methicillin-resistant strains was much higher: bacteriostatic effect of red light was observed already at the dose of 60 J/cm2. At the maximum dose of irradiation used in our experi- ments, the inhibition of bacterial growth is 67%. Pre-treatment of bacterial cells by Photoditazin significantly enhances the inhibitory effect of the laser light. The bacteriostatic action of the red laser radiation on the methicillin-sensitive S. aureus strain is manifested when the doses of 90 J/cm2 is applied. The degree of inhibition of growth of bacterial colonies of the methicillin-resistant S. aureus strain is also significantly higher after the preliminary action of Photoditazin than with the action of only the laser.