Intraductal papillary mucinous neoplasms (IPMNs) may present with clinical and radiological pictures resembling those of chronic pancreatitis (CP).To compare the clinical and epidemiological characteristics of patients suffering from CP with those of patients suffering from IPMN. To assess whether CP is associated with an increased risk of developing IPMN.In our departments, from 1981 to 1998, we prospectively followed 473 patients suffering from CP, including 93 cases of chronic obstructive pancreatitis (COP), and 45 patients with a histologically confirmed diagnosis of IPMN. Another 6 patients had an initial diagnosis of CP and a subsequent diagnosis of IPMN.Patients with IPMN were more often female (females 53 vs. 15%; p < 0.001), were older (mean age 63.1 vs. 42.8 years; p < 0.001), drank less alcohol (19 vs. 107 g/day; p < 0.001) and smoked fewer cigarettes (mean 8 vs. 21 cigarettes/day) than CP patients. These results were also confirmed when considering only patients with COP. The 6 patients with a subsequent diagnosis of IPMN were males (p n.s.) with a mean age of 51.4 years (p < 0.05). Only 1 patient was a drinker (p < 0.05) and 4 were smokers (p n.s.). Comparing CP and IPMN, logistic regression analysis selected sex, age, alcohol and smoking, whereas only sex and age were selected when comparing COP vs. IPMN.In general patients with IPMN present different epidemiological characteristics than those with CP and the subgroup with COP. The clinical and pathological features suggest that in most cases IPMN is the cause of CP and not vice versa.