A program to reduce the incidence of erythroblastosis fetalis was started in Nova Scotia in 1964. Up to the end of 1984, 120 fetuses received 247 intrauterine transfusions. The survival rate was 45.6% in the first 10 years of the program and 66.7% in the next 11 years. For fetuses at or over 26 weeks' gestation the figures were 51.5% and 73.7% respectively. Postpartum prevention was started in 1968, with administration of Rh immune globulin (RhIG) to Rh-negative unimmunized women within 72 hours after the birth of an Rh-positive infant. Antepartum prevention, started in 1979, consisted of administration of RhIG at 28 weeks' gestation to Rh-negative unimmunized women. The effectiveness of the prevention program was evaluated by enumerating the known cases of Rh(D) alloimmunization in the province from 1982 to 1984: 55 cases were identified, a rate of 1.5 per 1000 births instead of the expected rate of about 10 per 1000.