Objective To assess the diagnostic value of fiberoptic ductoscopy(FDS) on the nipple discharge. Methods The clinical data of fifty two consecutive patients with nipple discharge undergoing FDS from November 1998 to April 1999 were retrospectively analysed. Results A total of 62 ducts in 52 patients were successfully examined by FDS. Intraductal tumor of the breast was found in 14 cases(4 cancer and 10 papilloma). The diagnostic rate of FDS on intraductal tumor was 100%; and 85.7% of these patients were microlesions. Six cases were diagnosed as mastitis. Thirty two normal duct cavities presented just simple dilatation. In 73.7% of non tumor patients, the nipple discharge disappeared after irregation via FDS. Conclusions As a simple technique and a minimal traumatic endoscopy, FDS would be useful in detection of the microlesions of breast and might become a new diagnostic method of nipple discharge instead of ductography.