Objective: In the last 50 years a significant decrease in human fertility has been observed. Infertility is a common problem affecting one in six couples. The World Health Organization defined infertility as the inability of a sexually active couple to achieve pregnancy despite unprotected intercourse for a period of greater than 12 months. In 30% of infertile couples, the male factor is a major cause. There is accumulating evidence that occupational exposures contribute to male infertility. Men suffering from infertility problems may do well to look at their occupations, where exposure to certain substances and situations may be a contributory factor, if not a direct cause, of infertility. The purpose of this review article was to determine the association between male occupational exposures and infertility. Materials and Methods: The studies examined by the review include those published in the international scientific literature since 1990, and were identified through the search of MEDLINE using selected keywords. Results: Occupational factors have been divided into 5 groups: 1-Physical factors (Heat, Radiation, Noise), 2-Chemical factors (Smoking, Endocrine disruptors, Solvents, Drugs, Pesticides, etc.), 3-Psychological factors (Psychological disturbances and emotional stresses, Irregular work hours), 4- Exposure to Metals and Welding (Cadmium, Mercury, Chromium, Lead, Nickel, Copper, Manganese,etc.), 5-Physical load and Ergonomic factors Conclusion: Several occupational exposures have known or suspected deleterious actions to male reproductive function. For some specific agents, such as heat, ionizing radiation etc. the evidence is strongly supported in well-designed epidemiological studies. Additional studies need to be done to ascertain the effects of occupational factors on male infertility. Until then, men and their employers should work together to minimize exposure to these factors.