20 microsatellite polymorphisms: HUMHPRT, HUMD3S1358, HUMTH01, HUMACPP, HUMVWF, HUMD16S310, HUMD4S243, HUMTPO, HUMFES/FPS, HUMF13A1, HUMDHFRP2, HUMD11S2010, HUMD13S767, HUMD9S926, HUMD2S1328, HUMD14S306, HUMD18S848, HUMD5S818, HUMD7S820 and HUMFGA were analyzed in a worldwide survey covering five continents and allele frequencies are given. There is a high heterogeneity in allele frequencies among continents. A neighbor-joining tree based on Fst distance shows a pattern of differentiation that may reflect the role of drift in the development of genetic differences among humans. The variation found between continents confirms the usefulness of tetranucleotide microsatellites in human genetic variation studies.