Background: Insecticides poisoning is a major problem worldwide, especially in developing countries. The most extensively utilized types are pseudocholinesterase (PChE) inhibitors, predominantly organophosphorus compounds and carbamates. They are metabolized by microsomal oxidases to oxygen analogues, which are active neurotoxic metabolites. These oxygen analogues are further hydrolyzed by the serum arylesterase; paraoxonase (PON1), which appears to play a pivotal role in their detoxification. Objectives: This study aimed to 1-Identification and quantitation of common insecticides in acutely poisoned patients presented to Assiut University hospitals. 2- Detection of paraoxonase and cholinesterase levels in poisoned patients. 3- Evaluate the prognostic value of pesticide type and enzymes level in relation to the severity of insecticidal poisoning. Methods: This case-control study was conducted on 50 patients who have been admitted to the Emergency Unit and Intensive Care Units in Assiut University Hospitals along with 50 controls. Age, residence and sex were matched. History and clinical data and other related laboratory investigations were gathered for each patient. Blood plasma samples (5ml) were collected from patients on admission alongside controls then analyzed for level of pseudocholinesterase (PChE) and paraoxonase (PON1) enzymes activity by a spectrophotometer. The insecticide types were identified using Gas Chromatography/Mass spectrometry (GC-MS). Results: The patients were mostly males, of young age group and residing in rural areas. The mode of poisoning was mainly accidental by oral route (66%). Tachycardia, tachypnea and hypotension were most commonly presenting muscarinic signs. The detected insecticides were mainly of the organophosphate types specifically malathion. A highly significant decrease in PChE and PON1 level were detected in patients compared to controls that the decline in their levels was also significantly associated with the severity of acute poisoning. A positive correlation was also observed between PChE and PON1 levels. Conclusion: the present study identified more than one type of pesticides mainly of organophosphate category among acutely poisoned patients. Furthermore, it pointed to those persons with higher paraoxonase activity and less cholinesterase inhibition may have a better chance of toxic effects amelioration