A screening program was implemented to identify hrB– donors. D– C+, D–C–, and D+C– samples from African-American donors were typed with multiple examples of anti-hrB and anti-hrB-like, and one example each of anti-V and anti-VS. Of 75 D–C+ donors, 4 (5%) typed as hrB–, and 14 others had weak or variable expression of hrB. Of these 18 individuals, 15 were V–VS+, and 3 were V+VS+. No hrB– sample was found in 90 C– donors, 26 of whom were V+VS+, and 1 was V–VS+. A review of our records of 44 hrB– patients and donors studied earlier revealed that at least 12, and possibly as many as 30, carried