Joint disease involves multiple components of the joint, like bones, articular cartilages, synovium, joint capsule and pericapsular soft tissues. Since the lesion can begin in any of the structures, radiologist has to evaluate all these elements. Arthritides have been broadly classified as: (a) Degenerative or Osteoarthritis, (b) Inflammatory—rheumatoid and non-rheumatoid, (c) Infective, mainly pyogenic and tubercular, (d) Metabolic and endocrinal, (e) Neuropathic, (f) Miscellaneous. In each group, etiology, pathology, radiological appearances-common and uncommon have been discussed in details with plenty of illustrations. Miscellaneous group includes pigmented villonodular synovitis, synovial osteochondromatosis and collagen disorders like scleroderma, systemic lupus and dermatomyositis.