The smoky shrew (Sorex fumeus) and the masked shrew (S. cinereus) are common soricids in mature southern Appalachian hardwood forests. To better understand the role of body size and niche relationships in these syntopic species, 12 50- by 50-m plots were established in the Pisgah National Forest of western North Carolina. Trapping was conducted from August through November 1996 and from March through August 1997 using Y-shaped drift fences with associated pitfalls. Prey items and microhabitat components were measured to examine correlations with abundance of shrew species. Total shrew captures (n = 176) included 105 (59.7%) Sorex fumeus and 41 (23.3%) S. cinereus. Smoky shrews were significantly larger than masked shrews in both mass and body length. Stepwise multiple regression analyses determined that a combination of litter moisture, class 5 coarse woody debris (CWD), and number of invertebrates and mountain dusky salamanders (Desmognathus ochrophaeus) was the best predictor of S. fumeus abundance (R² = 92.8%), whereas S. cinereus abundance was best explained by a combination of litter moisture, leaf-litter depth, class 3 CWD, and invertebrate size (R² = 57.7%). Microhabitat niche breadth (MB) of S. cinereus (2.11) was narrower than that of S. fumeus (2.27). Linear discriminant function analysis revealed significant ecological separation between the 2 shrew species (D² = 0.62), despite high levels of microhabitat niche overlap (MO = 65.7%). The larger body size of smoky shrews may provide an advantage in that it can use parts of the microhabitat that are inaccessible to its smaller congener, thereby reducing interspecific competition.