Data concerning 15 infants and children with late-presenting (more than 8 weeks) Morgagni hernias over the last 20 years (1966 to 1986) have been reviewed. Ten of the cases were clinically normal on presentation, and the most common symptoms and signs were gastrointestinal and respiratory. Only one child presented with acute symptoms. Five had previously normal chest x-rays, and two others had an incorrect initial radiologic assessment. Chest x-ray was the most common diagnostic test; preoperative barium studies were performed in three patients. Twelve patients had other major congenital abnormalities. Fourteen of the 15 had surgery, usually within days of presentation. At operation, 10 of the 14 hernias contained a hollow viscus, nine had a sac, and four had abnormal bowel fixation. Postoperatively, two children had radiologic evidence of impaired diaphragmatic motility. There was no mortality in this series. Overall, late-presenting Morgagni hernias are relatively benign.