Carabids were sampled in 2000 (pretreatment year) and 2003–2005 in experimental plots in southern Alberta, Canada, after a rotation of beans, wheat, and potato under sustainable and conventional farming practices. Each phase of the rotation was present in every year. Crop type had a stronger effect than sustainable treatment on carabid-expected species richness, diversity, and species composition. However, carabid activity density was consistently higher in plots under sustainable treatments than those maintained conventionally. Potato plots, which were sprayed with insecticide for pest control, showed a significantly lower carabid activity density than the other crops. These results support other studies showing the beneficial effect of sustainable farming on activity density of carabid beetles.