Forty-five pregnancies in patients with homozygous hemoglobin S disease and 9 pregnancies in patients with sickle cell-hemoglobin C disease are reported. An increased incidence of toxemic and infectious complications was noted. Severe anemia was seen quite often, and many patients developed some degree of cardiac decompensation. Bone pain crises were frequent. Many patients went into labor prematurely, and infants small for gestational age often were delivered. Perinatal mortality rates were 24% in homozygous hemoglobin S disease and 62% in sickle cell-hemoglobin C disease. Four maternal deaths attributable to these hemoglobinopathies are reported. Increased use of surgical sterilization and therapeutic abortion in these patients seems to be justified.