A retrospective cooperative survey allowed analysis of 151 cases of ulcers diagnosed by endoscopy (106), surgery (40), or autopsy (5). There were 58 primary ulcers, 21 aspirin-induced ulcers, 23 steroid-induced ulcers, and 49 stress ulcers. Up to the age of 7, the majority of ulcers (80%) were secondary; after 7 years, only 47.6%. The higher incidence was found in boys of all groups, especially after 7 years of age. Only aspirin-induced ulcers were located more often in the stomach (52.3%). A family history was present in parents and siblings of children with primary ulcers (31%) and aspirin-induced ulcers (23.8%). The secondary ulcers were often complicated: hemorrhage was nearly always present with aspirin induced ulcers (95.2%); perforation occurred principally in steroid-induced ulcers (30.4%), and stress ulcers (42.8%). Death occurred only in steroid-induced ulcers (8) and stress ulcers (21). Secondary ulcers rarely became chronic.