Population structure of Dungeness crab (Cancer magister) from British Columbia was evaluated from a survey of variation of eight microsatellite loci in eight populations. Genetic differentiation among the populations surveyed was observed, with the mean F_st for all loci 0.031 (SD = 0.007). The Alison Sound population in the British Columbia central coast displayed less genetic variation and was distinct from all other populations in British Columbia, with pairwise F_st values >0.12, over 20 times the differentiation in other comparisons. The results were consistent with a high level of retention of larval crabs within Alison Sound, owing to reduced water exchange between the sound and adjacent waters. There was no evidence for an isolation by distance model of population structure of Dungeness crab in British Columbia, but there was some indication of differentiation between a west coast Vancouver Island population and a population adjacent to the southern Strait of Georgia.