Background: Antipsychotics are a class of medications that are primarily used for treatment of psychosis especially schizophrenia. The most common cardio-toxic features of antipsychotics overdose are tachycardia, hypotension, and prolonged corrected QT interval. Aim: This study aimed at assessment of ECG changes utilization as a predictor of major outcome events in antipsychotic poisoned patients. Patients and methods: This prospective observational study was conducted at Tanta Poison Control Unit on 43 patients of both sexes with antipsychotics poisoning. For each patient, socio-demographic and toxicological data were collected, physical examination was performed, and routine investigations were measured. Electrocardiogram was done, and corrected QT was calculated. The severity of symptoms and signs of antipsychotics poisoning and related ECG changes were graded according to poisoning severity score. Results: This study revealed significant association between ECG grading and each of seizures, ICU admission, and in-hospital mortality. Significant association was also detected between corrected QT interval and ICU admission. Conclusion: It was concluded that, ECG changes could be used to predict mortality and major outcome events in antipsychotics intoxicated patients.