pigmentation and gastrointestinal hamartomas. Hamartomas are not generally regarded to be premalignant, but in the Peutz-Jeghers syndrome a number of authors have found the existence of malignancies in hreast, gonad as well as gastrointestinal tract. We studied 11 cases of Peutz-Jegher. syndrome admitted at Department of Surgery of Hanyiang University hospital and acquired the following results: The age ranged from 3 years old to 44 years old, with average age 16 years old. All patients had had mucocutaneous pigmentation since early infants, repeated episodes of abdominal pain due to intussusception, occult blood loss from the intestinal traqt, and anemia are main symptoms. Eight cases out of 11 cases had family history. The polyps distributed as follows: Jejunum (11 cases, 100%), ileum (9 cases, 81.896), colon (9 cases, 81. S), stomach (4 cases, 36.44), and duodenum (3 cases, 29. 3%). Colonic adenocarcinoma develqped in a 44 years old man. The development of malignancies in breast, gonad as well as gastrointestinal tract and recurrnce of polyps in GI tract required regular follow-up study.