A FORTRAN program, “Genestats” was designed to analyse genotypic and allelic frequencies in subpopulations. The genotypes of individuals gathered from electrophoretic analysis at one or more loci are submitted. The program subsequently calculates allele frequencies, determines if significant heterogeneity exists among subpopulations, tests for departures from random mating in subpopulations and calculates F-statistics. A description of the statistical methods is provided. Printout from analysis of allozyme data collected from field subpopulations of the house fly (Musca domestica L.) is provided to illustrate and evaluate the computational methods.