The ascaroid nematodes Contracaecum spiculigerum and C. multipapillatum were recovered in large numbers from the proventriculus of four species and 66 individuals of pelicaniform birds collected in Connecticut, Florida and South Dakota. Both species of nematodes were commonly observed to penetrate the mucosal wall of the proventriculus where they caused gross hemorrhages and ulcerations. Microscopic lesions consisted of compression atrophy of the glandular mucosa with generalized inflammatory infiltrations. Contracaecum may serve a beneficial role in the digestive physiology of cormorants by crawling through and breaking up ingested fish which facilitates the entrance of digestive enzymes. Wild-captured nestling cormorants held in captivity until maturity lost their nematode infections in three months suggesting that Contracaecum has a short life span.