A 28 year old man suffering from long-standing mitral stenosis with regurgitation received a mitral valve replacement using the Type 6310 Beall prosthetic valve. Total bypass lasted for 2 hours, during which period anesthesia was maintained with intermittent intravenous injections of small doses of morphine and d-tubocurarine. Toward the end of the operation, the patient was tracheotomized and required assisted respiration by a Bird Mark 7 respirator for 2 days. He regained consciousness immediately after the end of the operation, made a fairly uneventful recovery, and was discharged from the hospital on the 29th postoperative day. Literature was reviewed stressing special importance of maintaining adequate oxygenation, lightest possible anesthesia, adequate circulating blood volume, and of postoperative fluid and electrolyte balance. Early and late causes of deaths were also reviewed.