The Cougar (Puma concolor) is an apex predator whose occurrence and space- use patterns are closely tied to the abundance and vulnerability of ungulate prey. Deer (Odocoileus spp.) and Elk (Cervus elaphus) readily use residential portions of the landscape, but little is known of Cougar prey use within these environments. We used Global Positioning System and VHF relocation data from 20 Cougars to examine prey use in a wildland-urban landscape in western Washington. We tested for differences (α  =  0.10) between wildland and residential prey compositions using the Chi-square test of homogeneity and used an ANOVA fixed-effects model to determine the potential influence of residential development on the duration of Cougar presence on kills. We located 304 kills throughout the study area with Black-tailed Deer (Odocoileus hemionus columbianus, 55.3%), Beaver (Castor canadensis, 22.0%), and Elk (8.8%) constituting the bulk of Cougar diet. Wildland and residential prey compositions were significantly different, with Cougars killing a higher proportion of Deer, Beavers, and Mountain Beavers (Aplodontia rufa) in wildland areas and more Coyotes (Canis latrans), Raccoons (Procyon lotor), Opossums (Didelphis virginiana), and domestic species close to residential development. Kill location did not have a significant effect on the duration of stay regardless of species killed, nor was the effect of location significant when comparing kills of the same species. Cougar diet in wildland-urban forests of western Washington is diverse, but Cougars do not appear to shift their space-use patterns to take advantage of non-ungulate prey close to residential development. However, long-term management of Cougars in wildland-urban environments may require an examination of ungulate presence in residential environments to ensure that these populations do not encourage Cougar presence in habitats close to people.