Pesticides are a large and heterogeneous group of chemicals which have long been used to control and repel pests in different fields.The organophosphates are the most widely used pesticides in industry, agriculture and houses. This study intends to evaluate the effectiveness of obidoxime therapy for reactivation of cholinesterase enzyme and its correlation with severity of poisoning among organophosphorus poisoning cases presented to Mansoura poisoning control unit (received oxime as aline of therapy) and Damietta general hospital, (did not received oxime as aline of therapy) during the period from 1st March 2015 to the end of February 2017. A total number of 303 patients presented with acute anticholiesterase poisoning (150 in Damietta and 153 in Mansoura Emergency Hospital). A total of 250 cases were diagnosed to be organophosphorus by TLC {112 in Damietta and 138 in Mansoura emergency hospital} and only 200 of them were included in this study according to exclusion criteria. Data on evaluation of obidoximes in treatment of organophosphorus (OP) poisoning incorporating the maximal clinical parameters and comparing the two groups in an unbiased manner, revealed that the use of obidoximes decreased the required dose of atropine and duration of hospital stay when compared with atropine alone. It is clear that there may be potential benefit from oximes as acetyl cholinesterase (AChE) activity is clearly increased by treatment.