Phenotype distributions and allele frequencies of adenylate kinase and esterase D were determined for four Canadian populations. In two population samples from southwestern Ontario, allele frequencies at both loci were similar to those of European populations. In two northern, indigenous populations, the allele AK2 was not detected. There was variation at the EsD locus with EsD2 having a frequency of 0.176 in an Indian population, and 0.156 in an Eskimo population.