The Karpathian frog ( Pelophylax epigenesis ) is considered the most endangered frog in Europe. Here we evaluate their food ecology and examine 76 individuals from the two known populations using the stomach lavage method. We also measure body weight, length from snout to cloaca and mouth width of frogs, and width and length of prey. The Pelophylax epigenesis diet, composed mainly of Coleoptera, Aranean, Isopoda, and Hymenoptera, is similar to that of other species of green frogs in the adjacent areas. The two populations differ in body size but present similar values for prey abundance and frequency. It appears that P. epigenesis follows a strict feeding strategy. Studying the availability of prey in their habitats will provide valuable information.