A task force for the EULAR standing committee for clinical trials determined the methodological and logistical approach required for the development of evidence-based guidelines for treatment of knee osteoarthirits (OA). Methods. The first stage was the selection of treatment modalities to be considered. The second stage comprised a search of the databases of all European-language publications. All of the relevant studies were quality scored. The third stage involved determination of key clinical propositions by expert consensus employing a Delphi approach. The final stage involved ranking of these propositions according to the available evidence. A second set of propositions relating to a future research agenda was determined by expert consensus. Results. Seven hundred and forty-four studies presented outcome data of the effects of specific treatments on knee OA. Quantitative analysis of treatment effect was possible in only 61 studies. Recommendations for the management of knee OA based on currently available data and expert opinion are presented. Proposals for a future research agenda are highlighted. Conclusions. These are the first clinical guidelines on knee OA to combine an evidence-based approach and a consensus approach across a wide range of treatment modalities. It is apparent that only certain clinical propositions are supported by substantial research-based evidence. There is thus an urgent need for future well-designed trials to address key clinical questions.