We used a new magnetic resonance endoscope with a small radiofrequent (RF) coil attached to the tip. After insertion of the instrument into the second portion of the duodenum, patients were placed in a magnetic resonance imaging (MRI) scanner. Fast spoiled gradient-recalled acquisition (SPGR) pulse sequences were used for this method. After plain scans, six axial scans were performed after intravenous injection of 20 ml of gadolinium-diethylenetriaminepentaacetic acid (DTPA) contrast medium. We performed endo-MRI on 22 patients, 13 with pancreatic carcinoma, four with pancreatic cystoadenoma, and five with other diseases. In the patients with pancreatic carcinoma, tumors were delineated as low-intensity masses after injection of contrast medium. Dilated main pancreatic ducts were clearly defined. In eight patients with carcinoma of the head of the pancreas, tumors were clearly defined in seven (87.5%) cases. In the eighth case, motion artifact prevented acquisition of a clear image of the pancreas. For diagnosis of invasion of the portal vein, the sensitivity of endo-MRI was 80%. the specificity was 100%, and overall accuracy was 87.5%. The new technique of endo-MRI allows the precise diagnosis of pancreatic tumors.