BACKGROUND: HLA-B*15 alleles encode molecules belonging to several serologic subtypes, B62, B63, B71, B72, B75, B76, and B77. Using the conventional serologic typing method, assignment of B15 subtypes has often been prone to error specifically in samples exhibiting either an ambiguous or a B15 homozygous reaction pattern. The goal of this study was to establish a supplementary DNA typing method for accurate assignment of B15 subtypes in 'problematic B15 positive samples'. METHODS: B*15 specific gene amplification was performed using a pair of PCR primers that specifically annealed to B*15 and B*46 alleles. Nested PCR was applied to the amplified DNA using 14 sequence specific PCR primer sets. DNA sequencing was used to clarify the assigning of samples exhibiting discrepancies between the results obtained by B*15-specific nested PCR-SSP typing and serology. RESULTS: The B*15-specific nested PCR-SSP typing could clearly discriminate the 9 B*15 alleles expressed in the Korean population. In application of the system to 30 B15 positive serologically typed samples, 4 exhibited discrepancies between serology to PCR-SSP results. DNA sequencing results obtained from the samples were concordant with those from B*15-specific nested PCR-SSP typing. CONCLUSIONS: The established B*15-specific nested PCR-SSP method is superior to serology in accuracy and resolution. Therefore, the method will be useful as a supplementary DNA typing method to clarify HLA-B assignments of 'problematic B15 positive samples' in Koreans.