[en] A report is given of the most recent assessment of doses from medical exposures published by UNSCEAR in 1982. Medical irradiation is characterised by the high instantaneous rate of exposure, by the fact that it generally involves limited parts of the body and by the large variability of the doses received by the patients. Under such conditions, expressing the doses as averages over the whole exposed population has little significance; on the contrary, collective doses may provide some indication of the overall impact of medical sources. It is estimated that the annual collective effective dose equivalent from medical diagnostic procedures may amount to about one-half of that received from natural sources in developed countries. In developing countries the same quantity could be ten times lower in view of a correspondingly lower rate of examinations. Thus, the annual collective effective dose equivalent applying globally over the whole world could amount to about one-fifth of the collective dose equivalent from natural sources. (author)