Ten patients with marked hemolytic anemia secondary to prosthetic cardiac valve replacement are presented. Although the etiology of this disorder is not understood, available evidence supports the concept of blood destruction secondary to turbulence around valves as the primary factor. These studies illustrate the technical difficulties associated with reoperation and the disappointing results which often follow. Emphasis is placed on the role of iron replacement and folic acid therapy in association with moderate reduction in exercise. This regimen has produced gratifying results in the management of these patients.