Between January and December 1996, the food habits of a relict population of jaguars were studied in 220 km² Linhares Forest Preserve, which comprises much of the remaining old-growth Atlantic Forest of Espírito Santo, Brazil. Fecal analysis indicated opportunistic feeding on 24 prey species (N = 101 scats). Mammals represented 87 percent of the total items, followed by reptiles (9.8%) and birds (2.8%). Considering prey weight, 23.4 percent of the items weighed 1–3 kg, 40.5 percent were 3–10 kg, and 27.7 percent weighed more than 10 kg. Analysis of relative prey frequency and biomass indicated that the diet was concentrated in two prey types: long-nosed armadillo and white-lipped peccary. Literature data suggest that forest jaguars rely on the same mammal prey over their entire geographic range.