Objective: Organic phosphates (OP) bind covalently to acetylcholinesterase (AChE) and acetylcholine (Ach) accumulates in the synaptic cleft. Administering oximes before aging process causes breakage of the covalent bond between OP-AChE, and allows reactivation of AChE. Pralidoxime (PAM) is the most commonly used oxime. The purpose of this study is to determine the best PAM regimen for the length of hospitalization, the need for mechanical ventilation and reduction of the duration of mechanical ventilation in patients presenting with OP poisoning. Material and Methods: Thirty four patients included in this study were organized according to the order of enrollment, randomized and divided into two groups. Seventeen patients in the group I were given a single dose of 2 g/20 min PAM infusion (bolus dose), while 17 patients in group II were administered a dose of 2 g/20 min followed by 6 g/24 hours PAM infusion (bolus and infusion). Clinical signs and symptoms as well as the serum butyrylcholinesterase (BCHE) levels were used to verify the patients' diagnoses. Results: There were no significant differences between the groups. Conclusion: We suggest that PAM bolus plus infusion therapy does not have any advantage over a single dose of bolus PAM therapy the in treatment of OP poisoning.