Necrotizing enterocolitis of infancy is a fulminating disease, not entirely restricted to the neonatal period, but with a predilection for the premature infant. Our review of the world literature and our own experience with 20 proven cases indicate that the roentgenographic findings have generally permitted accurate diagnosis. One or more of the following major roentgenographic findings were present in virtually all of the reported cases: pneumoperitoneum; pneumatosis intestinalis; portal venous gas; and small bowel distention. The colon was not usually distended unless it was extensively involved with roentgenographically apparent pneumatosis. The presence of pneumatosis on preliminary plain roentgenograms is an absolute contraindication to contrast enema examinations which are generally not needed to establish the diagnosis. The differential diagnosis from other pathologic processes is discussed.