Rh immune globulin (RhIG) has been used to prevent alloimmunization in D– recipients of apheresis platelet transfusions from D+ donors that may contain up to 5 mL of D+ red blood cells (RBCs). Granulocyte concentrates contain approximately 30 mL of RBCs and it has been necessary to give D– recipients granulocyte transfusions from D+ donors. Intravenous RhIG has not yet been demonstrated to be effective in preventing D alloimmunization with granulocyte transfusions. Four D– recipients received multiple D+ granulocyte transfusions from D+ donors and multiple injections of intravenous RhIG at a standard dose of 600