SUMMARYA new HLA‐B antigen, HLA‐B7Qui that appears to be a variant of HLA‐B7 has been identified. This antigen, which is HLA‐Bw6 associated, reacts with approximately two‐thirds of cytotoxic antisera stimulated by HLA‐B7 or B27 that lack a B27 or B7 component, respectively. All anti‐B7+27 antisera (stimulated by either B7 or B27) react with B7Qui as do most B22‐stimulated sera possessing a B7 component. However, sera stimulated by B60, with or without a B7 component, fail to react with B7Qui.Family studies show the B7Qui allele to be unique to the haplotype –HLA‐A32 CW6 B7Qui Bf*S C4A*6 C4B*1 DR11 DQ7 (GL02). Six Caucasoid subjects on the panel of 6861 HLA‐typed potential bone marrow donors have this antigen (phenotype frequency, 0.08745%; gene frequency, 0.04473%). Work undertaken during the 11th International Histocompatibility Workshop (Reekerset al., 1992) showed that B7Qui has the same isoelectric point as HLA‐B702 and HLA‐B703 (Bpot) and that B7Qui is distinct from the HLA‐B7 variants B703, B7SL