We have previously described HLA-DRB1 typing using polymerase chain reaction - based microtiter plate hybridization (PCR-MPH) method, which is suitable for routine "mass" DNA typing of HLA. In this study, we have extended this method to allele typing for HLA-classI. Three sets of primers were used for group specific amplification, and then PCR products were typed for five HLA-A2 (10 probes) , three HLA - A26 (5 probes ) , and four HLA-B61 (6 probes) alleles, which are unable to be classified by serological techniques. The results in this study were well concordant with those obtained by previous typing using the PCR based SSO method. In these allele typing procedures, group specific amplifications can be performed by the identical conditions and moreover, all conditions for MPH are exactly the same as those for DRB1 typing. These characteristics are great advantages for a routine typing.