The experience from eight open studies and five controlled trials of cyclosporine in rheumatoid arthritis is reviewed. A therapeutic approach characterized by low initial doses and slow upward titration appears to minimize the toxicity while retaining sufficient amounts of the efficacy seen with higher doses, although the onset of benefit is slower. In short-term studies, renal dysfunction and other side effects appear to be reversible. However, studies of combinations of cyclosporine and other slow-acting agents, long-term studies, and more renal biopsy specimens are needed to determine the appropriate use of this agent. Cyclosporine holds promise as an important addition to the therapeutic armamentarium for patients with rheumatoid arthritis.