Background/Aims: No reliable nationwide clinical data about chronic pancreatitis (CP) was available in Korea. The etiology and clinical features of CP were investigated using a multicenter nationwide study. Methods: 814 cases of CP were enrolled retrospectively over the past 4 years at 13 hospitals. The following data were obtained from all patients: etiology, symptoms, complications, and surgery. Result: Alcohol (64.3%) was the major cause of CP and idiopathic CP (20.8%) was the second most common form. Mean patient age was 50.6 years and the male:female ratio was 6:1 (24:1 for alcoholic CP vs. 2:1 in idiopathic CP, p < 0.001). Diabetes (31.6%), pseudocysts (28.4%), biliary stricture (13.9%), and pancreatic ascites (6.6%) were the main complications. Of these, diabetes (35 vs. 26%) and pseudocyst (33.7 vs. 21.9%) were more frequent in alcoholic than in idiopathic CP. Pancreatic cancer developed in 25 patients (3.1%) during follow-up and their mean age was 59.1 years. Conclusions: In Korea, alcohol is the most common etiology of CP. Moreover, diabetes and pseudocysts are frequent complications, especially in alcoholic CP, and pancreatic cancer development is not infrequent.