In connection with the radiation protection for medical personnel, the logarithmic normal distribution of their exposure doses has been examined, which is a prerequisite for the practice. The data were the doses measured by film badges from April, 1976, to March, 1981, for physicians, radiation technicians and nurses. The dose measurement by film badges was carried out monthly, 12 times a year; the values given were mrem/year. For the probability distribution of exposure doses, the following items were surveyed: comparison between three types of the profession and the kinds of film badges, i.e. for X-ray and ..gamma..-ray, the linearity of the logarithmic normal distribution for the types of medical institution, and comparison in the linearity between Japan and other countries. The fitting to linearity was found to be very good.