Between May 1995 and June 1999, we studied denning ecology of 8 1 barren-ground grizzly bears (Ursus arctos) equipped with satellite radio-collars within a study area of 235,000 km(2), centered 400 km northeast of Yellowknife, Northwest Territories, Canada. All dens were located on well-drained slopes ((X) over bar = 25.3degrees, SE = 1.20, it = 55). Choice of den aspect was nonrandom (chi(2) = 12.4, d.f. = 3, P0.5 in) shrubs (Betula glandulosa and Salix), the root structures of which supported ceilings of dens. Selection of denning habitat by bears was significantly different from random (G = 127.67, d.f. = 6, P < 0.0001). Bonferroni confidence intervals indicated that esker habitat was selected more than expected by chance (P < 0.10). Den entrance occurred primarily in last 2 weeks of October. The majority of bears emerged from dens in the 1st week of May.