The use of pesticides has extensively grown in the last decades, regardless of the economic level of the countries. This led to great improvements in agriculture but also a threat for human health. Short term effects are quite well known through approval procedures for pesticides. On the other hand, long term effects are not properly assessed. A review of epidemiologic knowledge is presented here. Epidemiologic studies on pesticides have found associations with long-term effects on health mainly in three fields: cancer (especially hematological cancer), neurotoxic effects (polyneuropathy, neuro-behavioral hazards, Parkinson's disease), and reproductive disorders (infertility, birth defects, adverse pregnancy outcomes, perinatal mortality). These conclusions have been obtained despite difficulties in exposition assessment due to the retrospective nature of the studies. But the continuous development of pesticide use in agriculture, and also in domestic environment, emphasizes the need for epidemiologic studies on long-term effects of pesticides relying on accurate exposure assessment.