The first case of acquired immune deficiency syndrome (AIDS) in pregnancy is reported. The patient, a drug addict, presented with lymphadenopathy, pulmonary infiltrates, and skin lesions of Kaposi's sarcoma, a tumor rarely found in young women in this country. The helper T-lymphocyte to suppressor T-lymphocyte ratio showed the profound inversion characteristic of this cell-mediated immune deficiency disease. Chemotherapy, a combination of doxorubicin, bleomycin, and vinblastine, was initiated during pregnancy. A growth-retarded infant was delivered vaginally. At four months of life, the infant had no apparent evidence of immune deficiency. Transplacental transmission of AIDS has not, as yet, been demonstrated. The social factors, clinical and laboratory features, and the controversies surrounding this new disease are discussed.