Groove pancreatitis is a rare form of chronic pancreatitis. Distinction between pancreatitis and pancreatic carcinoma is often difficult. Two cases of groove pancreatitis diagnosed by endosonography are described. A hypoechoic pattern between the duodenal wall and pancreas was clearly imaged in both patients. Narrowing of the second part of the duodenum and evidence of bile duct obstruction were also found. The endosonographic diagnosis was confirmed either by surgery or follow-up examination.