SUMMARYSeveral sequence‐specific oligonucleotides (SSO) were designed based upon available sequences of HLA‐DRB 1 genes which are associated with HLA‐DR serotypes. Targets for these SSO were polymerase chain reaction (PCR) products using primers specific for the second exon of DRB genes. In view of practicality, a hybridization system was developed which was independent of temperature or composition of the hybridization buffers, hence uniformly applicable to all SSO, yet allowing discrimination based upon one nucleotide mismatch only. The SSO typing results were compared with HLA serological typing and a high correlation was observed