The causes of death among the 93 chemists belonging to a cohort of 857 men, who graduated from the Schools of Chemical Engineering at the Royal Institute of Technology (KTH), Stockholm, and the Chalmers Institute of Technology (CTH), Gothenburg, Sweden, during the years 1930 to 1950, were studied. The group was followed until the end of 1974. There was a significant increase of cancer, particularly of leukemias/malignant lymphomas and of urogenital tumors. The study indicated that chemists, who continued with laboratory work for at least a few years after graduation and specifically worked with organic compounds, displayed an increased frequency of death from cancer.