Objective: Osteoarthritis (OA) is one of the most prevalent musculoskeletal diseases. Collagen derivatives are candidates for disease-modifying OA drugs. This group of derivatives can be divided into undenatured collagen (UC), gelatine and collagen hydrolysate (CH). Collagen derivatives are marketed as having direct chondroprotective action and reducing complaints of OA. This review summarizes the evidence for the effectiveness of symptomatic and chondroprotective treatment with collagen derivatives in patients with OA. Methods: Eligible randomised controlled trials (RCTs) and quasi-RCTs were identified by searching PubMed, Embase and the Cochrane Central Register of Controlled Trials until November 2011. Methodological quality was assessed using methods of the Cochrane Back Review Group. Results: Eight studies were identified: six on CH, two on gelatine, and one on UC. The pooled mean difference based on three studies for pain reduction measured with the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index comparing CH with placebo was -0.49 (95% Cl -1.10-0.12). However, some studies report significant between-group differences in pain when measured with a visual analogical scale (VAS) or other instruments, or when CH is compared with glucosamine sulphate. For Conclusions: There is insufficient evidence to recommend the generalized use of CHs in daily practice for the treatment of patients with OA. More independent high-quality studies are needed to confirm the therapeutic effects of collagen derivatives on OA complaints. (C) 2012 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.