Wide spread use of pesticides in the production system, persistence in the environment and their varying toxicity make them a major components of public health consideration. Pesticide residues have been reported to cause cancer, epilepsy, liver and kidney dysfunctions. Owing to the adverse effects of pesticides, international community had signed Stockholm convention which entered into force on 17 May 2004. Biological monitoring of pesticides in blood provides evidence of exposure of the body to pesticides and gives an indication of the body burden of the pesticide residues. Monitoring of organochlorines in blood is most appropriate because these pesticides are lipophilic in nature. Similarly, monitoring organophosphate concentrations in blood or blood products (serum, plasma) offers several advantages. The parent compounds could be monitored directly in blood. Nepal still has 70 MT (Metric Tones) of obsolete pesticides dumped across the country. The present study has been conducted in school children of Nepal, located adjacent to a warehouse containing 50.9 MT of obsolete pesticides since 1975, out of which 35.40 MT were organochlorines. DDT (Dichloro Diphenyl Trichloroethane), Endosulphan and residues of chlorpyrifos were detected in blood samples with levels of 0.079, 0.098, 0.245 mg/l, respectively. Among DDT metabolites pp' DDE (Dichloro Diphenyl Dichloroethylene) and pp' DDT were detected. Among endosulphan residues, levels of alphaendosulphan, betaendosulphan and endosulphan sulphate were 0.034, 0.023 and 0.041 mg/1, respectively. Distribution of pesticides based on the basis of sex, age, food habits and rural/ urban habitation did not clearly indicate any pattern. Water, air, dust and soil might be the major sources of these pesticides in those school children of Nepal as pesticides were being continuously leaked from a warehouse and making their way into the environment. Recurrent problems like nausea, vomition etc during wind blowing were reported by the students. No work was previously done regarding the presence of pesticides in human blood in Nepal so far and this is the first report of its kind.