It is estimated that about 4% of cancer mortality is attributed to occupational risk factors. Due to long latency periods it is often difficult to establish causal relationships. Thoracal cancer accounts for about 88% of all compensated occupational cancers in Germany. Most important exposures and diseases are asbestos-related lung cancer, asbestos-related malignant mesothelioma and radiation induced lung cancer (by Radon and its decay products). Lung cancer caused by nickel compounds, hexavalent chromium, arsenic and its compounds, coke oven gases and polycyclic aromatic hydrocarbons are rare. Silica-dust induced lung cancer can be compensated as occupational disease if a silicosis is present. In Germany every physician is obliged to notify a suspected occupational cancer as well as other occupational diseases.