Mitochondrial DNA (mtDNA) is a valuable tool for the study of recent human evolution because it is easy to analyse, is inherited uniparentally and has a relatively rapid rate of evolution. mtDNA analysis has been used extensively for the elucidation of the pattern of migrations of human populations. Several studies have focused on the Pacific because Polynesia was settled by humans for the first time relatively recently and there is a wealth of archaeological and linguistic data to complement genetic data on the region. Results of mtDNA analyses on modern-day Pacific populations indicate reduced genetic variability, and suggest that the Polynesians descend from people who migrated relatively recently from island Southeast Asia and that a population bottleneck occurred during the settlement of the central Pacific. Several informative polymorphisms have been identified in the hypervariable control region of mtDNA in modern-day Pacific populations that are helpful in tracing the ancestral affinities of these people. Studies of these mtDNA polymorphisms in ancient bones of prehistoric Pacific islanders indicate that the proto-Polynesian colonizers may have descended from the early settlers of island Melanesia. Although fraught with technical difficulties, studies of ancient DNA can provide valuable evidence on the genetic affinities of past peoples.