Background: Multiple medications have proven efficacy for the primary prevention of coronary heart disease (CHD), but the appropriate patient population remains controversial. Even in the presence of multiple cardiovascular risk factors, many patients are not considered high risk and are not offered preventive medications despite proven efficacy. Methods: We analyzed a prospective cohort of 1,710 consecutive ST-elevation myocardial infarction (STEMI) patients treated in a regional STEMI system from May 2007 to July 2010 and enrolled in a comprehensive database that includes preadmission medications. Results: Of the 1,707 patients analyzed, 1,180 (69.1%) did not have known CHD before their event; and 482 (41.7%) of those patients had premature events (men < 55 years old, women < 65 years old). In patients without known CHD, cardiovascular risk factors were abundant (52.1% had hypertension, 43.6% had dyslipidemia, 41.4% had a family history of CHD, 58.5% were current or former smokers, and 14.9% were diabetic). Despite the high prevalence of risk factors, only 24.1% were on aspirin, 16.1% were on a statin, and only 7.8% were taking an aspirin and statin. Use of preventive medications was even less common in patients with premature events, including aspirin (15.2% vs 30.2%, P value <.001), statins (11.1% vs 19.5%, P value <.001), and the combination (5.6% vs 9.4%, P value <.001). Conclusions: Approximately 70% of a contemporary STEMI population did not have known CHD before their event, and > 40% of those events would be considered premature. Despite the significant burden of cardiovascular risk factors, use of preventive therapy was alarmingly low in patients presenting with STEMI.