OBJECTIVE: To examine the reliability and validity of a new French questionnaire assessing patient satisfaction with their osteoarthritis (OA) treatment. METHODS: Item generation: Semi-structured interviews were performed among 20 osteoarthritis (OA) patients and 10 clinicians. Interviews were recorded, transcribed and analyzed. Content validity and cognitive debriefing of the first version of the Arthritis Treatment Satisfaction questionnaire (ARTS) was evaluated by 10 OA patients. Validation study: Principal Component Analysis, multi-trait analysis, internal consistency (Cronbach's alpha) and known group validity were performed on a cross-sectional sample of 797 OA patients. Test-retest was assessed on 133 clinically stable OA patients. Test-retest reliability was estimated with the Intraclass Correlation Coefficient (ICC). RESULTS: Patients were on average 67.5 years old (SD = 10.4), 64.5% were women, 26% had OA of the hip, 58% had OA of the knee, and all patients had suffered from OA for an average of 7 years (SD = 6.4). The resulting ARTS questionnaire comprised 18 items consisting of a clear four dimensional structure measuring advantages of treatment, treatment convenience, apprehensions about treatment and satisfaction with medical care. Scores were calculated using the mean of items in each dimension. Cronbach's alpha's ranged from 0.63 for treatment convenience to 0.86 for advantages of treatment. ICC ranged from 0.61 for advantages of treatment to 0.75 for treatment convenience. ARTS significantly differentiated patients according to presence of side effects, regular practice of physical activity, perceived pain and indices of severity. CONCLUSION: Results provide evidence for the good psychometric properties of this first treatment-satisfaction questionnaire specific to osteoarthritis. The responsiveness of the ARTS questionnaire over time is still to be documented.