Organochlorine compounds are widely distributed in the world and may persist in both the environment and living organisms. They are fat-soluble compounds and people are usually exposed to them through food, inhalation or dermal contact. They are classified as POPs (persistent organic pollutants), as they persist in the environment for a long time and move up through the food chain. DTT and other synthetic pesticides, polychlorinated dibenzodioxins (PCDD), polychlorinated dibenzofurans (PCDF) and polychlorobyfenils (PCB) are among the most diffused POPs worldwide. Experimental studies show that some of these chemicals have endocrine disruption activity and particularly that they can alter the thyroid function. Furthermore, recent studies in humans show that exposure to some organochlorine compounds may increase the risk of type II diabetes mellitus. This review provides a synthesis of the results of epidemiologic studies regarding the association between organochlorines exposure and thyroid diseases and diabetes. We included published studies with measures of internal dose of exposure (usually, serum concentration) in adults. We retrieved 22 studies for thyroid diseases and 22 on diabetes. Overall, we found contrasting results among the studies, with about half of them showing a statistically significant association between serum concentration of organochlorines and the diseases investigated.