Jack Siemiatycki has contributed to several areas of health research, most notably cancer epidemiology. He developed novel and influential methods of exposure assessment to investigate environmental and occupational causes of cancer, and has carried out large population-based studies of several types of cancer. He is among the most frequently cited epidemiologic results in the authoritative Monographs on Evaluation of Carcinogens of the International Agency for Research on Cancer – a WHO agency. He has more than 140 peer-reviewed publications and countless invited presentations, and he has been an invited expert on nearly 100 Boards, Advisory Councils and Expert Panels.