RESUMEN
The risk associated with the Chernobyl fallout is the product of radiation dose and risk factor per dose unit. The radiation doses originate from inhalation of radioactive particles, ground irradiation from deposited nuclides and internal irradiation caused by contaminated food. In Sweden the largest dose contribution is due to external radiation. The deposition has been mapped by aerial measurements and in situ high-resolution gamma measurements at ground level over the whole country. On the basis of these measurements, population-weighted doses for external radiation have been estimated. Whole-body measurements on randomly selected individuals have been performed in order to estimate the average dose from internal irradiation. The collective dose, i.e. the sum of all individual doses, has been estimated to be about 1500 man-Sievert for the first year after Chernobyl and 5000-7000 man-Sievert for a 50-year period. Using a risk factor of 0.02 fatal cancers per man-Sievert the Chernobyl fallout over Sweden might cause 100-200 fatal cancers.