Background: Acute organophosphorus (OP) poisoning is a critical toxicological problem with substantial morbidity and mortality. Aim of the study: Identifying applicable predictors of intensive care unit (ICU) admission and mortality in acute OP poisoning. Patients and Methods: This study was conducted on patients with acute OP poisoning admitted to Tanta University Poison Control Center from January 2023 to December 2023. Personal and toxicological history, findings of clinical examination, and laboratory investigations were collected from the patients' files. Poisoning Severity Score (PSS) and Rapid Emergency Medicine Score (REMS) were documented. Patients were sub-grouped considering ICU admission and mortality. Results: Out of 66 patients, 15 (22.7%) required ICU admission and 6 (9.1%) died. The age of patients ranged from 18 to 66 years, 59.1% were males, and 80.3% were from rural areas. Suicidal poisoning and oral route were found in 57.6% and 72.2%, respectively. Pulse and respiratory rates, creatinine, urea, serum glutamic pyruvic transaminase (SGPT), and serum glutamic-oxaloacetic transaminase (SGOT) were significantly higher while Glasgow Coma Scale, partial arterial oxygen pressure (PaO2), pH, and serum bicarbonate (HCO3) were significantly lower in adverse outcome groups. Both PSS and REMS predicted ICU admission with excellent performance (AUC = 0.971 and 0.955, respectively) and mortality with good performance (AUC = 0.890 0.879, respectively). Conclusion: PaO2, pH, serum HCO3, creatinine, urea, SGPT, SGOT, PSS, and REMS could predict adverse outcomes of acute OP poisoning. Recommendations: REMS could be recommended as a simple and applicable tool to predict ICU admission and mortality in acute OP poisoning.