Organophosphorus poisoning has significant clinical importance, especially in the developing countries, due to its major health consequences. The study evaluated role of obidoxime in reactivation of cholinesterase (ACHE, BuCHE) enzymes in acute organophosphorus (OP) intoxicated patients. It was conducted on group I: 50 patients received obidoxime therapy after acute OP intoxication, and group II: 50 patients did not receive obidoxime. Patients were subjected to neurological evaluation, determination of ACHE and BuCHE levels. Results revealed that there were statistically significant differences between both groups regarding clinical outcomes, with variability of significance regarding initial and final levels of cholinesterase enzymes. It was concluded that BuCHE enzymes' levels can be considered sensitive biomarker for OP exposure and severity, while, ACHE activity reflected the recovery.