Turgida turgida is a common parasite of the stomach of the American opossum in Florida. Worms were usually found attached to the greater curvature of the corpus of the stomach. Ulcers always occurred at the site of the attachment. Large ulcers were associated with groups of adult parasites and were found in the oldest experimental infections. Turgida turgida fed on food within the stomach of the opossum and attached to the stomach wall when not feeding. Third- and fourth-stage larvae were found in opossums in Florida mainly from May to August suggesting that this is a major period of transmission.