A proposed novel allospecificity, HLA-Cw6.2, has been reported to be commonly found (approximately 25%) in Spanish Gypsies. Full-length cDNAs of the allele (Cw*1502) coding for this antigen have been cloned in this study. A simple PCR-SSO method for its detection has been standardized and a correlation with the serologic Cw6.2 phenotype has been established. This specificity has been also detected in the homozygous typing cell RML. Although the primary structures of Cw*1502 and Cw*0601 are not closely related, they share specific motifs that may account for their serologic cross-reactivity. Two novel HLA-C alleles (Cw*12022 and Cw*0602) are also reported.