Elderly populations are increasingly represented among patients with acute coronary syndrome (ACS), and advanced age has been identified as an important risk factor for death and adverse outcome in patients with ACS treated invasively. Although considerable data have demonstrated a prognostic benefit of early revascularization in ACS particularly in high-risk patients, elderly patients with ACS are treated invasively less often than younger patients because older age is thought to be an independent predictor of mortality after percutaneous coronary intervention (PCI) in ACS. Over the past 5 years, a total of 54 ACS patients over 85 years old were treated. The 6-month survival rate was around 50% in the non-PCI group (n = 12) and around 80% in the PCI group (n = 42) (P < 0.05). Cardiac death occurred in 6 patients in the PCI group and in 6 patients in the non-PCI group. The rates of both cardiac death and all-cause death were significantly lower in the PCI group. The change in ADL score before and 6 months after the procedure was from 1.57 to 1.59 in the PCI group and from 2.25 to 2.20 in the non-PCI group. PCI for elderly patients with ACS is safe and life saving, and does not reduce the ability to perform activities of daily living. PCI should be recommended even for octo-nonagenerians with ACS.