A cuse with single tenign insulinoma which was located in trc tail af pancreas is presented. It should be pinte out that a diagnosis of organic hypeinsulini::m may be difficult lo establish because of the aljpictl symptoms and signs. Whipple triad. laboratory, angiographv are important for diagnsis. Tle treatment of choice is early surgery with removal Df insulinoma. However if no tumor is found by careful palpation of the entire pancreas. resection of the neck. body and tile of the pancieas is iustified.