Acute renal insufficiency after percutaneous coronary artery intervention (PCI) is a strong predictor of adverse events. However, the effect of chronic renal impairment on the long-term outcomes after PCI has not been well established. The aim of this study was to evaluate the incidence of deteriorated renal function during the chronic phase after PCI and its impact on clinical outcomes. We enrolled 282 consecutive patients who underwent PCI and had serum creatinine measured during the chronic phase (at least 3 months after PCI). We divided the study population into two groups: an advanced group that had an increase in stage of chronic kidney disease during the chronic phase, and a preserved group that included the remainder of the study population. There were 43 patients in the advanced group. We evaluated the incidence of major adverse cardiac events (MACE) that included all-cause death, nonfatal myocardial infarction, and rehospitalization with heart failure or angina pectoris. The rate of rehospitalization for heart failure and angina pectoris was significantly higher in the advanced group than in the preserved group (19.0% vs 6.8%, P < 0.01). In multivariate Cox regression analysis, the advanced group was associated with MACE (hazard ratio 3.50, 95% confidence interval 1.49-8.22, P < 0.01). Deterioration of renal function during long-term follow-up after percutaneous coronary intervention was associated with adverse cardiac events.