Distribution of a single nucleotide polymorphism in the TP53 codon 72 (Arg/Pro) was studied in Southeast Asia and Oceania where information about this polymorphism was lacking. A polymerase chain reaction restriction fragment length polymorphism method was employed to genotype a total of 733 subjects from 12 populations in insular Southeast Asia and Oceania. These populations have been classified as either an Austronesianspeaking group or Papuan-speaking group. The p53Arg frequencies ranged from 0.06 in the Seramese to 0.62 in the Kahayan with an average frequency of 0.38. No significant correlation between the p53Arg frequency and latitude was observed in the 12 populations tested (P > 0.05), whereas a significant correlation was obtained for the relationship between frequency and longitude among 9 Austronesian or the whole 12 populations tested (P < 0.01). A longitudinal cline of the p53Arg frequencies may reflect the history of the Austronesian's migration and local admixture with indigenous Papuan speakers who had probably harbored low p53Arg frequencies.