Global Positioning System (GPS) data collected using radiocollars have allowed researchers to identify sites where predators have killed prey, but this method has yet to be compared with scat analysis, a more traditional method of determining diet composition. We analyzed 211 scat samples and compared composition of prey items with 266 kill sites found using GPS radiotelemetry data on cougars (Puma concolor) in the Cypress Hills of southeast Alberta and southwest Saskatchewan, Canada. Scat and kill site results showed significantly different occurrences of prey items; scat samples were better able to detect small mammals. However, larger prey made up >90% of the biomass of cougar diets, and when restricting the comparison to ungulate prey, both methods estimated nearly identical biomass consumed. As expected, GPS telemetry is biased against small prey but the method provides results comparable to scat analysis for larger prey that make up the majority of biomass consumed. © 2011 The Wildlife Society.