Because the medical use of x-rays and radioisotopes is gradually increasing for diagnosis and therapy, radiation workers, special doctors, nurses and radiological technicians have occupational exposure. Procedures for monitoring external exposure of personnel include the wearing of a filmbadge or a pocket chamber. The results of filmbadge monitoring in Yamaguchi University Hospital for the last 10 years were described. In 1964, the total number of filmbadges that radiation workers used during a 2 week period of radiological examination and therapy was 610. This has been increasing yearly, and in 1972 it was 1999. Radiological technicians generally had low occupational exposure, and about 90 per cent of their filmbadges were exposed to less than 10 mR. Approximately 65 per cent of the filmbadges that nurses used were less than 10 mR, but some nurses who worked in radium therapy at the isotope ward suffered large doses. Some nurses had occasionally exposure higher than 100 mR in radiological examination. Some doctors sustained an occupational exposure of more than 150 mR. From these data, some problems on radiation monitoring using a filmbadge were discussed.