35 cases of Mallory-Weiss syndrome among 277 cases of upper gastrointestinal bleeding were ascertained by endoscopy at department of internal medicine St. Columban's hospital. The mean age was 41.6 years. All of 35 cases were found in male. Combined disease were gastritis(15 cases), peptic ulcer(7 cases) and esophageal varix(3 cases). The most common precipitating factor was vomiting, 22 cases among the 28 cases of vomiting(80%) developed after drinking. Endoscopic finding revealed active bleeding in 5 cases, blood clot without active bleeding in 22 cases, and scar change without bleeding evidence in 8 cases. Most cases had had hematemesis after active bleeding but 5 cases had had only melena without hematemesis. The Mallory-Weiss lacerations were located at stomach in 16 cases(46%), at esophagogastric junction in 11 cases(31%) and at esophagus in 8 cases. On the view of gastric direction, 14 cases were on anterior wall side, 9 cases were on posterior wall side, 11 cases were on lesser curvature side and one case was on great curvature side. Single lacerations were more common than multiple lacerations. (Korean J Gastrointest Endosc 17: 329-334, 1997)