The oldest old comprise the fastest growing segment of the US population. However, data are limited regarding the treatment and outcomes of ST-segment elevation myocardial infarction (STEMI) in this age group. We analyzed consecutive patients with STEMI>or=85 years old at a single center. Quality of life was assessed using the EQ-5D Index (range -0.11 to 1.00) and EQ-VAS (range 0 to 100). Of 1,847 patients admitted from 2002 to 2007 with STEMI, 73 (4%) were >or=85 years old (range 85 to 94). Median time from symptom onset to hospital arrival was 3 hours. Cardiogenic shock occurred in 33%. Primary percutaneous coronary intervention (PCI) was performed in 70% of patients, and the procedural success rate was 94%. Evidenced-based therapy included aspirin (97%), clopidogrel (93%), beta blockers (82%), angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (74%), and statins (86%). The in-hospital mortality rate was 32%, and it was 54% in those with cardiogenic shock. Long-term follow-up was obtained in 96% of hospital survivors at a median of 429 days. Survival rates in patients discharged alive were 75% at 1 year and 65% at 2 years. Cardiogenic shock was the only independent predictor of in-hospital mortality (odds ratio 3.8, 95% confidence interval 1.2 to 11.7, p=0.02), and primary PCI was the only independent predictor of long-term survival (hazard ratio 0.3, 95% confidence interval 0.1 to 0.8, p=0.02). Mean EQ-5D Index was 0.78 and mean EQ-VAS was 70.5. In conclusion, in the oldest old with STEMI, aggressive treatment is associated with reasonable long-term survival and excellent quality of life. The exception may be patients presenting with cardiogenic shock, for whom short-term mortality remains exceedingly high.