In rheumatoid arthritis (RA), due to its superior contrast resolution and tomographic nature, magnetic resonance (MR) imaging can depict soft tissue and joint involvement better than plain radiography. Active synovitis and pannus are shown by a wide variety of contrast on T1- and T2-weighted images. They are markedly enhanced by intravenous gadolinium-chelate injection. Fat-suppressed T1-weighted imaging with gadolinium enhancement is the most sensitive technique to demonstrate these tissues. Compared with plain radiography, MR imaging is more sensitive and equally specific in the diagnosis of early RA compared with plain radiography. MR imaging is useful in the diagnosis and treatment of patients who are suspected of having early RA.