Use of pesticides have contaminated every ecosystem on the earth since pesticide residues have been reported in water, air, soil, crops, non-target plants and animals. Due to the toxicity, pesticides are potentially hazardous to humans, animals, other organisms, and the environment. Therefore, people who use pesticides or regularly come in contact with them, must understand the relative toxicity, potential health effects, and preventative measures to reduce exposure to the products. Symptoms of pesticide poisoning in human are either topical (develop at the site of pesticide contact) or systemic (occur away from the original point of contact as a result of the pesticide being absorbed into and distributed throughout the body). Common signs and symptoms of acute exposure to active ingredients of insecticide include abdominal pain, diarrhoea, dizziness, excessive salivation and tearing, headache, loss of consciousness, Malaise, muscle twitching and weakness, nausea, nervous system depression, pinpoint pupils, respiratory depression, seizures, sweating, vomiting, coma and death in severe case. Exposure of pesticides may result into fatal diseases like cancers, leukaemia and asthma. The risk of health hazards due to pesticide exposure depends on toxicity of the ingredients and the level of exposure. Additionally, children, pregnant women and aging populations are more sensitive to the effects of pesticides. This review provides an overview on harmful effects of pesticides on human health with reference to routes of human exposure, risks of exposure to human and impact on human health