In order to study the seasonal variation and habitat preference of carabids, I sampled using pitfall traps in various habitat types at Mont-St-Hilaire, southern Quebec, from the beginning of June until the end of October 2007. I caught 1193 individuals belonging to 53 species. Among the 16 most abundant species, nine were caught predominantly in early summer, five in mid summer, and four showed two peaks of activity, one in the early summer and one in the fall. There was no significant difference in terms of species richness or abundance between hardwood and mixed forests. On the other hand, ground beetle populations differed between wet and dry areas, and between forested and open or ecotonal areas. The ecotone between forest and meadow had the highest diversity and the highest abundance of carabids. Furthermore my analysis showed that several species were reliable indicators for various habitat characteristics such as proximity to a water body, forest type, and openness.