Objective. Describing the level and factors affecting the physical activity practices of knee osteoarthritis (OA) patients. Design. Propective epidemiological study. Patients and Methods. 548 knee osteoarthritis patients were interviewed via self-administered anonymous questionnaires. Main Outcome Measurement The main outcome was physical activity level, evaluated by the International Physical Activity Questionnaire (short version) (IPAQ). Secondary outcomes included sociodemographic and clinical data, comorbidities, as well as barriers to and facilitators of practicing regular physical activity evaluated over 24 specific elements. Results. The study population’s mean age was 67.6 years (SD 7.9), including 73.9% women and 30.9% obese individuals with a mean body mass index (BMI) of 28.2 kg/m2 (SD 5.7). Multi-joint osteoarthritis (OA) affected 92%, 71.6% of whom had comorbidities. The mean Visual Analogue Scale (VAS) pain intensity score was 4.5/10 (SD 2.5), 51.4% better than the Patient Acceptable Symptom State (PASS). Mean WOMAC function was 36.6/100 (SD 20.7), 57.5% better than PASS; 67% of patients used analgesics, half of them at least once a week. According to the IPAQ, 42.6% of patients reported high activity levels, 38.6% moderate, 18.8% low, the median IPAQ total activity score was 2628 metabolic equivalent of task (MET)-min/week and time spent sitting was 257.1 min/week. Only a third of patients received non-pharmacological treatment corresponding to the latest recommendations. Variables significantly related to inactive/minimally active physical activity levels were BMI (p=0.0294), gender (p=0.0008), and biomedical barriers, related to self-efficacy (p=0.0118). Conclusions. The OA study population was less active, more sedentary, and had more comorbidities and more barriers to physical activity practice than the overall population. This study could help better adapt health care measures, while taking into account patients’ overall status, including symptoms of OA pathology and comorbidities, providing tailored educational strategies with respect to physical activity.