Individual accumulated doses were determined by electron paramagnetic resonance spectroscopy of tooth enamel in Chinese medical diagnostic X-ray workers. Dose determination was performed using a specially developed automatic spectrum processing procedure. The determined dose values owing to X rays for the three workers with entry year (the year they began their career as medical diagnostic X-ray workers) in the 1950s ranged from 435 to 903 mGy, the converted effective doses ranged from 91 to 190 mSv.