Osteoarthritis (OA), the commonest arthropathy, targets specific joints e.g. the knees, hips, interphalangeal joints, and first carpometacarpal joints. Most patients develop symptoms in their middle or older age. Usage-related (’mechanical’) joint pain, short-lived morning stiffness, and locomotor restriction are the common presenting symptoms. Pain at extremes of movement and joint line tenderness may be present in early disease. Crepitus, bony enlargement, and reduced range of movement suggest more severe OA. Advanced OA is characterized by rest pain, night pain, muscle wasting, and deformity. Notably, symptoms and signs of inflammation are absent or only modest, although mild-moderate effusions are not uncommon at the knee. OA may be diagnosed on clinical grounds alone in the at-risk age group, in the presence of typical symptoms and signs. Radiographic changes of OA are commonly asymptomatic. In general there is poor correlation between symptoms, signs, radiographic changes, and disability in OA, and due care should be used to differentiate the ’disease OA’ from the ’illness OA’. More inflammatory symptoms and signs suggest coexistence of calcium crystal deposition. Evaluation of people with OA should include targeted assessment for treatable comorbidities such as depression and obesity that compound disability from OA.