Background: Organophosphates are highly toxic compounds for human beings. Organophosphate compounds (OPCs) poisoning by unintentional or suicidal ingestion is associated with high morbidity and mortality, particularly in developing countries. Aim of the study: Assessing the prognostic value of red cell distribution width (RDW) and white blood cells (WBCs), hemoglobin and platelet count on severity and outcome in patients with acute organophosphate poisoning in conjunction with clinical signs using the Peradeniya Organophosphorus Poisoning (POP) score. This is in addition to evaluation and comparison between RDW with pseudo choline esterase (PChE) level as early OPCs poisoning predictor. Methods: A prospective cross-sectional study was done on 100 acutely OPCs intoxicated patients admitted to Poison Control Center Ain Shams University Hospitals (PCC-ASUHs) from June 2019 till December 2019. All cases were clinically evaluated. RDW was done on admission and after 24 hours while WBCs, hemoglobin, platelets, PChE level and arterial blood gases (ABG) were estimated immediately after admission prior to treatment. Results: High RDW values indicated poor prognosis. There was a highly significant correlation between RDW values and the need for mechanical ventilation (MV). There was a significant correlation between high WBCs count, severity of OPCs poisoning and the need for MV. Lower mean pH, higher mean PCO 2 , lower mean HCO 3 , lower mean PChE levels, and higher mean WBCs count were noted in patients on MV compared to patients without MV. Conclusion: RDW values on admission can be a reliable predictor of severity and outcome in contrast to PChE levels which showed nonsignificant correlation with severity. Additionally, there was a significant correlation between WBCs with the need of MV. RDW on admission can predict the need for mechanical ventilation with sensitivity (58.97%), specificity (83.61%) at cutoff value more than 14.4. RDW on admission had a sensitivity of 75% and specificity of 73.75% with a cut-off value of 14.3 in predicting mortality in patients with OPCs poisoning. Recommendations: RDW is a simple parameter that could be used in assessing the prognosis of acute organophosphorus poisoning. WBCs count could also be used in those patients to predict the need of MV.