OBJECTIVES: The objective of this study is to assess trends in evidence-based therapy use and short- and long-term mortality over time among older patients with non-ST-segment elevation myocardial infarction (NSTEMI). BACKGROUND: With the prevalence of national quality improvement efforts, the use of evidence-based therapies has improved over time among patients with NSTEMI, yet it is unclear whether these improvements have been associated with significant change in short- and long-term mortality for older patients. METHODS: We linked detailed clinical data for 28,603 NSTEMI patients aged ≥65 years at 171 hospitals in the Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes with Early Implementation of the American College of Cardiology/American Heart Association Guidelines Registry with longitudinal Centers for Medicare & Medicaid claims data and compared trends in annual unadjusted and risk-adjusted inhospital and long-term mortality from 2003 to 2006. RESULTS: The median age of our NSTEMI study population was 77 years, 48% were female, and 87% were white. Overall, inhospital and 1-year mortality rates were 6.0% and 24.5%, respectively. When compared with patients treated in 2003, NSTEMI patients treated in 2006 were more likely to receive guideline-recommended inhospital medications and early invasive treatment. Inhospital mortality decreased significantly over the study period (5.5% vs 7.2% [adjusted odds ratio 0.82, 95% CI 0.67-1.00, P = .045] for 2006 vs 2003), but there was no significant change in 1-year mortality from the index admission (24.0% vs 26.0% [adjusted hazard ratio 0.99, 95% CI 0.90-1.08] for 2006 vs 2003). CONCLUSIONS: Between 2003 and 2006, there was a significant reduction in inhospital mortality that corresponded to an increase in the use of evidence-based NSTEMI care. Nevertheless, long-term outcomes have not changed over time, suggesting a need for improved care transition and longitudinal secondary prevention.