Stomach contents of 425 largemouth bass were identified and quantified using the Relative Importance (RI) index over three seasons (spring, summer, and fall) from Lake Lillinonah and Pickerel Lake, Connecticut. In Lake Lillinonah during spring, aquatic insects had the highest RI, followed by crayfish and fish (primarily white perch). During summer and fall, the RI of aquatic insects decreased, the RI of crayfish remained consistent, and the RI of fish approximately doubled. Fish (primarily bluegill) was the most important diet item of largemouth bass from Pickerel Lake during all seasons. Aquatic insects were the second most important diet item during spring and summer. In Lake Lillinonah and Pickerel Lake, the RI of aquatic insects decreased and the RI of fish increased with increasing fish length; aquatic insects were most important in largemouth bass less than 300 mm. In contrast to Lake Lillinonah where the RI of crayfish and fish were of equal importance in largemouth bass ≥ 380 mm, largemouth bass ≥ 380 mm in Pickerel Lake fed almost exclusively on fish. Our results suggest that food habits of largemouth depend on the type of lake system and the dominant prey types. In Connecticut lakes that lack suitable littoral areas and associated panfish species, largemouth bass may rely on pelagic fishes and crayfish as food sources.