BACKGROUND: Non-pharmacological treatments based on collagen as a dietary supplement are emerging as a new area of interest to support preventive or therapeutic effects in patients with osteoarthritis (OA). AIM: In a multicenter, prospective, double-blind, placebo-controlled, randomized study, to evaluate the effectiveness and safety of the use of the Artneo complex containing undenatured chicken collagen type II in patients with OA of the knee joints. MATERIALS AND METHODS: The study enrolled 212 outpatients from 12 centers in the Russian Federation with knee OA, stages II and III according to the Kellgren-Lawrence classification. The participants included 171 women (80.7%) and 41 men (19.3%), with an average age of 60.2±9.0 years (range: 40 to 75 years). The study population was randomly allocated in equal proportions into two groups using an interactive web response system (IWRS). Group 1 (Artneo) consisted of 106 patients who took one capsule of the drug once daily for 180 days. Group 2 (Placebo) also had 106 patients, with the dosage form and regimen identical to Group 1. During the treatment period, the following outcomes were assessed: WOMAC index, KOOS, pain according to VAS, quality of life using the EQ-5D questionnaire, and the need for NSAIDs. All patients underwent a clinical blood test, general urine analysis, biochemical blood test, and ultrasound examination of the affected knee joint. RESULTS: In a prospective, double-blind, placebo-controlled, randomized study, it was demonstrated that the Artneo combination, containing undenatured chicken collagen type II, has a positive effect on all clinical manifestations of OA: it effectively reduces pain, stiffness, and improves the functional state of joints and quality of life. It has a good safety profile and is superior to placebo in all parameters studied. CONCLUSION: The results of the study confirm the good effectiveness and safety of the Artneo combination in patients with OA of the knee joints.