This paper reviews the different series of thymectomies performed in patients with autoimmune diseases other than myasthenia gravis. It is possible that thymectomy can decrease the activity of T-helper lymphocytes or, alternatively, it may enhance the activity of T-suppressor lymphocytes, whose function is depressed in autoimmune diseases. Thymectomy was performed empirically for systemic lupus erythematosus and rheumatoid arthritis. The therapeutic benefits were questionable. Conflicting results were reported for thymectomy against autoimmune hemolytic anemia. Several trials were conducted to assess the therapeutic value of thymectomy in multiple sclerosis. Benefits were achieved only in relapsing-remitting but not in chronic-progressive multiple sclerosis. The effect of thymectomy in autoimmune diseases associated with myasthenia gravis were also reported. The authors conclude that thymectomy as treatment for autoimmune diseases other than myasthenia gravis is not elective therapeutic choice and it is acceptable only in selected cases.