Chronic pancreatitis is most frequently associated with alcohol abuse. This should however not always automatically be accepted as the presumed cause. When the history is doubtful, uncommon etiologies must be considered as is illustrated by the present case. A 38 years old man was in the past 20 years treated for chronic pancreatitis ascribed to ethylisme although he always denied this. When the diagnosis was eventually questioned, new investigations showed slightly elevated sweat electrolyte concentrations and a delta F508/R117H genotype compatible with cystic fibrosis (CF). Demonstration of mild respiratory abnormalities, obstructive azoospermia and CF in his brother supported this diagnosis. Although rarely, pancreatitis typically develops in the kind of CF patients with milder genotypes and less severe symptoms. Systematic analysis for genetic mutations in patients with idiopathic chronic pancreatitis (ICP) revealed however that this mild form of CF is a less exceptional cause than thought. As CF patients increasingly survive into adulthood this disease should be considered as a possible etiology in the differential diagnosis of pancreatitis at all ages.