Three clinical types of arthritis in meningococcal disease are presented; their classification is based on a review of the literature from 1887 and on experience with pediatric patients treated in Dallas, Texas. The most common type is arthritis complicating acute meningococcal disease; it occurred in 1,180 of the patients reviewed or approximately 5% of children and 11% of adults with meningococcal disease. Septic or allergic pathogenesis was documented in fewer than 5% of these, 1,180 patients. However, the search for an immunologic basis, conducted in a small number of patients, produced results suggesting that immune complexes are involved in many patients with sterile effusions. Large joints, especially the knee, were involved in 95% of the cases, and almost half the patients had polyarthritis. Chronic meningococcemia, an infrequently reported clinical entity, was accompanied more often by arthralgia than arthritis. Primary meningococcal arthritis, which is a rare form of acute septic arthritis, affected large joints almost exclusively and was polyarthritic in about one-third of cases. The management was the same for all types of meningococcal arthritis and consisted primarily of specific antimeningococcal chemotherapy. Evacuation of pus is recommended, since this treatment may be expected to shorten the relatively long symptomatic course. The prognosis for patients with meningococcal arthritis is excellent, and joint residua are rare.