An increasingly aggressive therapeutic strategy, improved treatment options, and encouraging preliminary results have attracted growing attention to the potential of magnetic resonance imaging (MRI) in the diagnosis, prognostication, and monitoring of rheumatoid arthritis (RA). MRI offers multiplanar imaging with unprecedented soft tissue contrast and high spatial resolution. Synovitis, the primary joint lesion in RA, can be detected and monitored. By contrast, conventional radiography shows only the late signs of preceding synovitis. Other soft tissue changes, such as tenosynovitis, tendonitis, enthesitis, joint effusions, and ligament and tendon tears, can be visualized. Unfortunately, the image resolution in most clinically available MR units is insufficient for evaluation of wrist joint cartilage. Preliminary data suggest that MRI is a valuable tool in the diagnosis and prognostication of RA. The superior sensitivity of MRI may be of major significance in both clinical trials and practice. In trials, MRI may allow reductions in the trial size and length because of its more sensitive separation of responders from nonresponders. Thus, although thorough validation is awaited, particularly concerning the reproducibility and prognostic value, MRI seems to be a very promising method for assessment of both established and early RA.