Seven infants with ductal dependent cyanotic congenital heart disease are reported. All were on prostaglandin E1 therapy to maintain ductus patency. All showed chest radiographic evidence of multiple masses indenting the stomach lumen (gastric thumbprinting). Other than feeding intolerance in two patients, the findings were incidental and disappeared with cessation of PGE1 therapy. "Gastric thumbprinting" appears to be a more common consequence of PGE1 therapy than actual obstructing antral masses (antral foveolar hyperplasia).