Background: Tricyclic antidepressants (TCAs) toxicity continues to be a major problem and an important cause of morbidity and mortality from poisoning all over the world. Aim of the study: to compare the effectiveness of poison severity score (PSS), acute physiology and chronic health evaluation (APACHE II) score and rapid emergency medicine score (REMS) for prediction of the need for intensive care unit (ICU) admission and mechanical ventilation (MV) in cases with acute TCAs toxicity. Methods: This retrospective observational study was conducted on 109 TCAs poisoned cases who were admitted to Tanta University Poison Control Center during the period from the first of January 2017 to the end of December 2020. Three scoring systems (PSS, APACHE II and REMS) were calculated for all cases at admission. Discrimination was evaluated using receiver operating characteristics curve and calculating the area under the curve (AUC). Results: The results of this study revealed that twenty-five cases needed to be admitted to ICU and 8 cases needed MV. The median of the three scores was significantly higher in cases that needed both ICU admission and MV. Although the APACHE II score has the best AUC value for prediction of ICU admission and MV (0.956 and 0.943 respectively), there was no statistically significant difference between the three scores. The AUC value of REMS comes next (0.931 and 0.925 respectively). Conclusion: REMS is rapid and simple score that can be easily assessed in emergency situations, it is recommended to be used for outcome prediction in TCAs poisoning.