Fluoride excess primarily effects dental and skeletal tissues, leading to a condition known as endemic fluorosis. The radiological and clinical features of endemic fluorosis vary in different parts of the world. The aim of this study was to investigate the clinical and radiological features of endemic fluorosis in Turkish patients. Physical examination and radiological investigations were performed in 56 patients with endemic fluorosis and 40 age- and sex-matched controls. Knee osteoarthritis (OA) was the main abnormality in both groups, both clinically and radiologically. The radiological severity of knee OA was greater in the endemic fluorosis group than in controls (P=0.01). Osteophytes at the tibial condyles and superior margin of the patellar articular surface of the femur, polyp-like osteophytes on the non-weight-bearing medial side of the femoral condyle, and popliteal loose bodies were detected more frequently in the endemic fluorosis group than in controls (P=0.0001). We suggest that the presence of atypically located osteophytes in the knees may be a feature of endemic fluorosis in Turkish patients and that endemic fluorosis may increase the severity of OA in the knees.