We performed a Japanese nationwide survey of pediatric-onset chronic nonspecific multiple ulcers of the small intestine between January 2000 and July 2013 in 176 institutions of pediatric surgery or pediatric gastroenterology and clarified the clinical features associated with genetic abnormalities in the Solute Carrier Organic Anion Transporter Family, Member 2A1 (SLCO2A1) gene. A total of 4 cases (3 girls and 1 boy) were diagnosed in this series, which had to be differentiated from Crohn disease, Behçet disease, tuberculosis, or drug-induced enteropathy. Clinical symptoms appeared in infants and accurate diagnosis required several years. Medical therapies for inflammatory bowel disease were administered in all patients; however, 2 of the 4 patients had mutation in the SLCO2A1 gene which are responsible for primary hypertrophic osteoarthopathy, and underwent strictureplasty or ileal resection after long-term follow-up. Pediatric gastroenterologists should include this new entity in the differential diagnosis of small intestinal ulcers and inflammatory bowel disease.