Current guidelines have recommended intravenous narcotics (IVNs) for patients with ST-segment elevation acute coronary syndromes (STEACS) and patients with non-STEACS (NSTEACS), although the safety of IVNs has been challenged. We performed a retrospective analysis of the 30-day outcomes stratified by IVN use among patients enrolled in a national survey, using logistic regression and propensity score analysis. Of the 765 patients with STEACS and 993 patients with NSTEACS, 261 (34.1%) and 97 (9.8%) had received IVNs, respectively. The patients with STEACS who received IVNs were more likely to undergo reperfusion (79.7% vs 55.2%, p <0.0001), received it more rapidly (median 59 minutes vs 70 minutes, p = 0.02), and were more likely to undergo coronary angiography and revascularization. No difference was found in hemodynamic status. The patients with NSTEACS who received IVNs were more likely to present with Killip class II-IV (39.2% vs 10.0%, p <0.001) and to have left ventricular systolic dysfunction (39.0% vs 17.0%, p <0.001). No difference was found in the use of invasive procedures. Using propensity score analysis, of 249 matched STEACS pairs, the rate of 30-day death was lower in the group that had received IVNs (2.4% vs 6.2%, p = 0.04), and this trend persisted after logistic regression analysis (odds ratio 0.40, 95% confidence interval 0.14 to 1.14, p = 0.09). Using propensity score analysis, of 95 matched NSTEACS pairs, no difference was found in the 30-day death rate (2.2% for patients receiving IVNs vs 6.3%, p = 0.16), even after logistic regression analysis (odds ratio 0.56, 95% confidence interval 0.14 to 2.33, p = 0.43). In conclusion, IVNs were commonly used in different scenarios-patients with STEACS were more likely to receive IVNs in the context of prompt reperfusion, and patients with NSTEACS were more likely to receive IVNs in the context of heart failure. In both scenarios, IVN use did not adversely affect the outcomes.