We report observations of the summer diet of Crotalus aquilus (Queretaro dusky rattlesnake) from an agricultural region near San Pedro de los Metates, municipality of Acambay, state of Mexico, Mexico. We recovered the remains of 12 individual prey items from 11 different snakes. Eleven of 38 (29%) snakes observed contained prey remains, including 6 mammals, 3 lizards, and 3 snakes. These observations suggest that C. aquilus consumes a diverse diet and that they may be more ophiophagous than many other rattlesnakes.