Objective. To evaluate the efficacy and safety of cytoflavin as an additional agent in the treatment of painful diabetic polyneuropathy and to analyze changes in the life quality of the patients studied. Material and methods. An analysis of treatment data was carried out in 61 patients with verified painful diabetic polyneuropathy, who were divided into 2 groups depending on the therapy regimen. Patients of the main group (n=36) at the start of the therapy with gabapentin additionally received cytoflavin: intravenously, slowly, 10 ml diluted in 0.9% NaCl 200 ml for 10 days, followed by switching to per os 2 tablets 2 times a day for 25 days. Patients of the comparison group used gabapentin in comparable doses as an analgesic symptomatic therapy. Clinical neurological and anamnestic methods were used to monitor and assess the condition of patients. Results and conclusion. Cytoflavin inclusion in the standard symptomatic treatment of patients with painful diabetic polyneuropathy contributed to a more pronounced decrease in the subjective assessment of pain (VAS scale) by the 10th day (42.8±2.4 mm versus 58.2±2.1 mm in the comparison group) and its maximum level of decline to 21—25 days. The achieved result was maintained by the 35th day (21.4±1.1 mm against 22.4±1.7 mm in the comparison group). At the same time, the quality of life of patients as assessed by SF-36 was significantly increased after treatment. The results obtained, along with the safety of the drug, allow us to recommend its inclusion in the treatment regimens for patients with this pathology.