The genetic variability at 20 enzyme loci in natural populations of Otiorrhynchus salicis Ström was studied by starch gel electrophoresis. Altogether 135 weevils were analyzed. The samples originated from a diploid bisexual population in Austria, from four triploid parthenogenetic populations in the Carpathian mountains, and from three triploid parthenogenetic populations in central Sweden. Altogether 16 different genotypes were found in triploid parthenogenetic populations. Two major types, comprising 39 out of the 76 parthenogenetic individuals, occur both in Scandinavia and in central Europe. The less frequent types can be derived from these through mutations. O. salicis is a flightless insect, which has been assumed to have overwintered the Würm glaciation in icefree refugia in Scandinavia. The overall genetic similarity found in the material suggests that the parthenogenetic race spread to its isolated Scandinavian area in postglacial times.