Genic variation within diploid bisexual and diploid and triploid parthenogenetic populations of Polydrosus mollis has been studied by starch gel electrophoresis. The diploid bisexual samples originate from Yugoslavia, the diploid pathenogenetic samples, numbering 69 individuals, have been collected from Finland and Sweden. Forty-eight triploid parthenogenetic individuals have been collected from central Europe. A total of 21 different overall genotypes were found in the parthenogenetic samples. Seven genotypes occur in more than one population. Parthenogenesis and polyploidy are a monophyletic condition in P. mollis. Even though the species can fly, its parthenogenetic populations are diverged into numerous genotypes. This is probably due to the stringent ecological requirements of the species, enhancing the isolation between populations. These genotypes have different geographic distributions.