DP gene typing using in vitro DNA amplification combined with sequence-specific oligonucleotide probes has recently been reported. The resulting DNA amplification was specific for the HLA-DPB locus. Typing for the individual DPB alleles was exclusively dependent on the hybridizations of the probes but hampered by close sequence homology between different DP alleles yielding complex patterns of reactivity with a panel of probes. We report the combined use of allele-specific DNA in vitro amplification and allele-specific oligonucleotides in typing for DPB1*03 and DPB1*06. Complete concordance with PLT typing was observed for the DPB1*03 alleles, while in the DPB1*06 group, at least three variant DPB1*06 alleles were identified which have not been described previously.