Restriction fragment length polymorphisms detected by the cDNA probe, pEMBL36, at the CALCA locus (calcitonin gene and calcitonin gene related peptide) on TaqI blots were examined in samples from Italian, Greek and Vietnamese migrants to Melbourne, Australia and in a sample of residents from the island of Tasmania, Australia. The frequency of the rarer of the two alleles of this polymorphism, A2 (8.0kb) varied between a low of 6% in Vietnamese to a maximum of 38% in Tasmanians. The frequency range of the A2 allele in European populations, however, was considerably less. Analysis revealed no significant heterogeneity for this polymorphism among either the European or European derived populations, and these combined data exhibited a frequency of 33% for the A2 allele. Though based on a very small Vietnamese sample this study suggests that the A2 allele is less frequent in those of Asian ancestry.