The history of the Rh problem is largely one of success. In some communities the incidence of hemolytic disease due to Rh-incompatibility approaches an irreducible minimum. Efforts to further decrease the pathology that results from Rh-incompatibility continue on two fronts: prevention of maternal sensitization and in utero treatment of the affected fetus. Unfortunately, while the controversy continues regarding the cost-effectiveness of routine antepartal administration of Rh immune globulin, many sensitizations still occur as a result of practitioner error. On the other front, technical advances in ultrasonography are assisting perinatologists in more direct treatment of affected fetuses. Nurse-midwives will continue to play a role in the prevention of sensitization through proper screening and follow-up of their Rh-negative clients. Education and direct involvement of the Rh-negative client in avoiding sensitization may be a first step in the prevention process.