A total 45 fish samples (Tilapia, Claris) were collected from EL-Bagoria, EL-Menofi drainage andBahrShibin for detection and determination of organophosphorus pesticides (diazinon, Malathionandchlorpyrifos). Organophosphorus pesticides could not be detected in Bahr Shibin. No diazinon in Tilapia from EL-Bagoria but mean value of of Malathion 5.50±2.0, chlorpyrifos 5.0±1.66but
from EL-Menofi drainage mean level of diazinon 3.33±0.65, Malathion 4.98±1.22 and chlorpyrifos3.0±0.71but in Claris samples, there were no diazinon, no Malathion, no chlorpyrifos from EL-Bagoria canal but
from EL-Menofi drainage, mean value of diazinon 6.8±1.42, Malathion 4.64±0.81 and chlorpyrifos4.0±0.96. Pesticides are one the main contaminant of water sources which are considered the natural environment
of fish. on the other hand, fish could be contaminated by pesticides either directly by gills breathingorindirectly through contamination of feeding items, so it is very important to analyze fish samples todetect
to what extent the rate of accumulation of pesticides residues in fish flesh and organs.