BACKGROUND/AIMS: The detection of iatrogenic Mallory-Weiss syndrome during the course of upper GI endoscopy is apparently rare. The aim of this study was identify the clinical features of the disease and associated medical conditions. METHODS: We retrospectively analyzed 46 cases (0.08%) of iatrogenic Mallory- Weiss syndrome identified from 54,188 consecutive upper GI endoscopies performed at our institution during a period of 85 months. RESULTS: A total of 36 patients (78.2%) had retching or belching during the procedure. Hiatal hernias were noted in 20 patients (43.5%). We identified a difference of the attack rate by sex and age for iatrogenic Mallory-Weiss syndrome; the disorder developed predominantly in men. All of the patients had a mucosal tear and oozing and 16 patients underwent endoscopic hemostasis. After being diagnosed with iatrogenic Mallory-Weiss syndrome, 17 patients underwent follow- up endoscopy and all of the patients showed good results without rebleeding. No patient showed a complicated clinical course. CONCLUSIONS: A small number of patients had iatrogenic Mallory-Weiss syndrome and most of the patients showed a good prognosis. If there is a predictable risk factor identified during an upper GI endoscopy or an associated medical condition, special care needs to be taken to minimize belching or retching.