Patterns of BglII, MspI, and TaqI DPα and DPß hybridizing restriction fragment length polymorphisms are compared with primed lymphocyte typing-determined specificities in 28 10th International Histocompatibility Workshop core cell lines. Correlation of specific RFLP patterns with most recognized DP types is confirmed, although the RFLPs do not distinguish DPw3 from DPw6. Analysis of DP-region nucleotide sequence data shows that the observed RFLPs are those expected to hybridize to the DPα and ß probes and are thus not due to cross-hybridization to other genes. The distribution of RFLPs in Chinese, Micronesian, South Indian, and white Australian populations is described. The most frequent DP specificity in Chinese is DPw5. In the other populations DPw4 is the most common specificity, although DPw6 is also relatively common in Micronesians. Four new DPα RFLP patterns and three new DPß patterns are described. There are also numerous unusual combinations of DPα and DPß alleles particularly in the South Indian population.