Purpose: This study examined factors associated with the hospitalization of patients who visited the emergency department (ED) after deliberate self-poisoning. Methods: The medical records of the patients, who visited the ED at a tertiary teaching hospital after deliberate self-poisoning between March 2017 and December 2019, were reviewed retrospectively. Results: Fifty-seven in the hospitalization and 236 in the discharge group patients were included. The mean age in the hospitalization and discharge group was 48.8±20.4 and 41.8±19.1, respectively (p=0.020). Univariate analysis revealed statistically significant differences in age (p=0.020), mental status (p<0.001), request for help (p=0.046), chronic disease (p=0.036), substance ingested (p<0.001), and risk rescue-rating scale (p<0.001) between the two groups (hospitalization group and discharge group). In multiple logistic regression analysis for predicting the hospitalization of patients after deliberate self-poisoning, the Risk-Rescue Rating Scale (RRRS) was identified (OR=1.493, 95% confidential interval=1.330-1.675, p<0.001). Receiver operating characteristics analysis of RRRS for the decision to hospitalize showed a cut-off value of 38.9, with a sensitivity, specificity, and area under the curve of 96.4%, 77.0%, and 0.949, respectively. Conclusion: The RRRS can be used to determine the hospitalization for patients who visited the ED after deliberate self-poisoning. Nevertheless, multicenter prospective studies will be needed to determine the generalisability of these results.