We investigated whether attempted percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) would improve the prognosis in patients with renal insufficiency at high risk of contrast-induced nephropathy (CIN). We analyzed 2,330 consecutive patients with renal insufficiency with or without CTOs who underwent coronary angiography or PCI from prospectively collected data. The long-term death and risk of CIN were evaluated among three groups: patients without CTOs (group A, n = 1,829), patients with un-attempted PCI for CTOs (group B, n = 142), and patients who underwent attempted PCI for CTOs (group C, n = 359). Overall, group B and group C (successful rate, 89%) patients had similar renal function and were not significantly associated with an increased risk of CIN (adjusted odds ratio [OR] = 0.88, 95% confidence interval [CI]: 0.41-1.93, P = 0.758). During a 2.33-year period (median), multivariate analysis demonstrated that attempted PCI for CTOs was independently associated with lower mortality (adjusted hazard ratio for death: 0.38, 95% CI: 0.18-0.83; P = 0.015). Attempted PCI for CTOs improved the long-term prognosis in patients with high-risk renal insufficiency and did not increase the risk of CIN.