The World Health Organization conducted a comparative risk assessment to ascertain the contributions of 26 risk factors to the global burden of disease. Five occupational risk factors accounted for an estimated 37% of back pain, 16% of hearing loss, 13% of chronic obstructive pulmonary disease, 11% of asthma, 9% of lung cancer, 8% of injuries, and 2% of leukemia worldwide. Virtually all cases of silicosis, asbestosis, and coal workers’ pneumoconiosis were work-related. Contaminated sharps injuries accounted for 40% of hepatitis B, 40% of hepatitis C, and 4% of HIV/AIDS infections among health care workers. Data limitations, primarily in developing countries, prevented the inclusion of other major occupational risk factors. These selected occupational risks accounted for about 850 000 deaths and 24 million years of healthy life lost each year. The deaths due to these selected occupational risk factors constitute only 43% of the International Labour Organization’s estimate of 2 million deaths worldwide due to work-related risks.