Wra is a low-prevalence antigen. Anti-Wra is a relatively common antibody present in approximately 1 in 100 healthy blood donors. Anti-Wra is reported to cause different degrees of hemolysis in transfusion and in HDN, ranging from benign to severe. This report describes an acute overt hemolytic transfusion reaction in a patient whose serum contained anti-Wra and who received a Wr(a+) RBC component.