BACKGROUND Few data are available on the efficacy of long stenting for lesions in unselected chronic total occlusion (CTO). OBJECTIVE The study was undertaken to evaluate the angiographic restenosis and long-term clinical outcomes after long stent implantation in patients with CTO. METHODS Our retrospective analysis includes a consecutive series of stent implantation in 220 patients with CTO. We compared angiographic restenosis, target lesion revascularization, and long-term clinical outcomes of short stenting (< 20 mm, Group 1, n = 113) with a concurrent series of long stenting (> or = 20 mm, Group 2, n = 107). RESULTS Angiographic follow-up was obtained in 174 patients (79.5% of those eligible), and the rates of angiographic restenosis were 19.3% in Group 1 and 33.7% in Group 2 (p < 0.05). In multivariate analysis, the postinterventional minimal lumen diameter was the only independent predictor of restenosis (odds ratio = 0.20, 95% confidence interval 0.08-0.49, p < 0.01). The angiographic restenosis rate was significantly lower in Group 1 than in Group 2 in patients with final minimal lumen diameter < 3.0 mm (28.9 vs. 55.9%, respectively, p < 0.05). However, the angiographic restenosis rate was not significantly different between the two groups in patients with final minimal lumen diameter > or = 3 mm (12.0 vs. 19.2%, respectively, p = NS). During the follow-up (29.1 +/- 10.8 months), there was no difference between the two groups in death, nonfatal myocardial infarction, and target lesion revascularization. CONCLUSIONS The use of long (> or = 20 mm) versus short (< 20 mm) stents in patients with CTO is associated with a higher angiographic restenosis rate, but there is an equivalent risk of restenosis in selected patients with relatively large-sized vessels.