Results of diagnosis and treatment in 32 patients with lower lip cancer using photodynamic therapy (PDT) with photosensitizer Photosense are represented. 15 patients had stage I of disease, in 12 – stage II and in 5 – stage III. Photosensitizer Photosense was administered at dose of 0.5 mg/kg body weight in 20 patients and at dose of 0.8 mg/kg – in 12 patients as single intravenous infusion. During the treatment the fluorescent diagnosis (FD) was performed. The average power of diagnostic laser irradiation was 2 mW, light dose on tissue surface was < 1 J/cm². Power density of therapeutic laser irradiation accounted for 150–300 mW/cm², light dose of one session was 200-300 J/cm². First session of PDT was performed 24 h after drug injection, the interval between following sessions accounted for 24 h. The number of session varied from 3 to 5. The results of FD showed the increase of fluorescent intensity in the center of tumor from 14.9 up to 150.8 r.u. 24 h after drug injection, this parameter in the normal mucosa increased from 13,4 to 88,3 r.u. The side-effects of PDT with Photosense included pain syndrome, which was managed by non-opioid analgesics in all 10 patients. The signs of phototoxycity were observed in 9 patients. Two months after PDT 22 (68.7%) patients had complete regression of tumor lesion, the response in 8 (25%) patients was defined as partial, 2 (6.3%) patients had stabilization of tumor growth.