The principles of determining exposure limits for carcinogens adopted in Poland, the European Union and in other selected countries of the EC are discussed in this article. Carcinogens and/or mutagens pose a direct health risk to people exposed to them. If carcinogens cannot be eliminated from the work and living environments, their exposure should be kept at the lowest possible level. To assess health risk for carcinogens it is necessary to determine the probability of developing a disease or of death from cancer as a result of occupational exposure to carcinogenic substances. Med Pr 2013;64(4):541–563