We describe a radiographic sign of infantile hypertrophic pyloric stenosis. This sign, elicited during firm compression of the barium-coated pyloric region, is a round or avoid filling defect caused by the hypertrophied pyloric muscle protruding en face into the gastric lumen. This filling defect typically reveals a barium-containing central depression or stellate indentation, representing the proximal end of the obstructed pyloric channel. This sign, like the closely related "shoulder sign", appears to establish the diagnosis of hypertrophic pyloric stenosis without need for filling of the pyloric channel or for additional radiographic maneuvers.