Osteoarthritis (OA) is the most prevalent chronic joint disease and one of the major causes of disability in the adult population. Although OA is considered a progressive degenerative process which involves the whole joint, articular cartilage and subchondral bone play a determinant role in its pathogenesis. In particular, metabolic-triggered subchondral bone damage, together with biochemical markers, are referred as important indicators of the disease. Magnetic resonance (MR) is the best imaging technique to detect and characterize such bone abnormalities. It represents an effective method through which to not only diagnose, describe and follow the course of OA but also to deepen our understanding of the natural history of the disease, with the ultimate purpose of attaining improved outcome in terms of therapy and prognosis. Even though MR has enormous potential, some diagnostic pitfalls may occur in clinical practice, hence an accurate clinical assessment of the patient is mandatory in combination with optimal imaging evaluation.