164 страниц. 2014 год. Scholars' Press The use of pesticides to control undesired plants, insects, and other organisms has become the major problem facing the industrialized world because despite of its success, it causes environmental and health problems. The problem then is how to detoxify and degrade residual pesticides in soil and water.microorganisms play the important role in the biodegradation and detoxification of the pesticides residues in soil and water. Terefore, the bioremediation of pesticides residues by microorganisms has become an important area of research.The aim of this work is investigating the ability of local microbial strains isolated from Fayoum governorate to degrade pesticides such as methomyl and dimethoate. The study was also aimed to determine whether the enzyme which responsible for the degradation, was located on plasmid or chromosomal DNA.