We examined the mating frequencies of queens in a social wasp, Dolichovespula arenaria (Vespinae) using DNA microsatellites. Five of the seven colonies supported the hypothesis of single mating by queens. The other two colonies supported two and three matings, with effective paternity of 1.48 and 1.91. Mean worker relatedness was 0.77 ± 0.09. In two of the four male-containing colonies, all were likely progeny of the queen. In the other two colonies workers produced 8 and 14% of the male wasps. Overall, 94.3% of the male wasps were likely progeny of the queen. These patterns are consistent with published studies of vespine wasps.