The accidental swallowing of foreign body is a common problem in the children. We describe the case of 37-month-old girl in whom a gastric ulcer was caused by the ingestion of three magnets. This case report demonstrates that if more than one magnet were swallowed, they should be removed even if there are no sharp edges and small size. Because the magnets will attract each other and hold the intestinal walls between them, causing necrosis and resulting in intestinal perforation or a fistula.