Photodynamic therapy effect on healing of radiation skin ulcer infected with Pseudomonas aeruginosa Objective. To reveal the effect of photodynamic therapy on the healing of experimental radiation skin ulcers infect ed with Pseudomonas aeruginosa. Materials and methods. The infected radionuclide was modeled by local X ray irradiation of the rat's hip skin at a dose of 85.0 Gy, followed by the application of Pseudomonas aeruginosa bacterial suspension to the surface of the ulcer. Photodynamic therapy (CTD) was performed with the help of a photon apparatus «Barva LED/630» and a photosen sitizer of methylene blue. The effect of PDT on the rate and quality of healing of an infected radionuclide was deter mined by comparing the histological and morphometric study of skin from the region of ulcer in animals from the control and treated groups of PDT. Results and conclusions. The presence of Pseudomonas aeruginosa in the radiation sickness caused an increase in the area of the wound cavity compared with the non infected radionuclide and to a significant inhibition of its healing processes. The addition of the infection factor reduced the activity of the reparative processes in the radiation sick ness by 20 % compared with the uninfected. The effect of photodynamic therapy contributed to complete healing on average one month earlier than in control groups.