A prospective cohort study was conducted on a series of cases involving 2988 patients (71.9% male), with an average age of 67 years, who were treated at the Sestre milosrdnice University Hospital from June 1, 2011, to January 1, 2019, with percutaneous coronary intervention due to their first myocardial infarction. The primary aim of the study was to examine the impact of prior chronic statin therapy on mortality in patients with myocardial infarction. The median follow-up period was 61 months. Patients were divided into two groups based on previous statin therapy. Overall mortality (until the end of the follow-up period) and short-term mortality (within 30 days of myocardial infarction) were analyzed. All-cause and cardiovascular mortality were analyzed separately. Out of the 2988 patients studied, 420 (14.1%) had previously been treated with statins, and this group showed a statistically significant higher burden of previously diagnosed atherosclerotic disease and cardiovascular comorbidities. The results of the study did not show a statistically significant difference in mortality between the observed groups, both short-term and long-term, thus confirming the null hypothesis. Observing all-cause mortality, it was noted that patients previously treated with statins died earlier during the follow-up period than those who had not been previously treated with statins. Independent predictors of mortality included: patient age, diabetes mellitus, peripheral arterial disease, ventricular tachycardia, and high Killip class at admission. When considering the type of infarction and angiographic characteristics, it was noted that patients treated with statins more often had NSTEMI and angiographically non-occlusive type of infarction, which was also a predictor of mortality. Among the laboratory findings and imaging results, hemoglobin levels and ejection fraction were shown to be independent predictors of mortality. This study demonstrated that the SCORE2 system effectively predicts all-cause mortality, regardless of prior statin use. Both high-risk and non-high-risk patients did not show different mortality rates depending on prior statin therapy.