BACKGROUND: In the era of drug-eluting stents (DESs), the angiographic rates of restenosis at later months have reduced dramatically but less completely. We compared parameters influencing the likelihood of restenosis after DES implantation in diabetic and nondiabetic patients. METHODS: Stented patients (n=619) with DESs were retrospectively reviewed for inclusion in the study from the PCI database. From this database, 211 (34.1%) out of 619 patients with 6 months angiographic follow-up had diabetes. Predictors of restenosis were identified with multivariate regression analyses. RESULTS: Restenosis (>50% of the luminal diameter stenosis) occurred in 32 of 408 (7.8%) nondiabetic and 32 (15.2%) of 211 diabetic patients (p<0.01). Multivariate parameters for predicting restenosis in the diabetic group were current smoking (OR = 3.21, 95% CI 1.46 to 7.08, p<0.01), higher C-reactive protein (CRP) (OR=1.62, 95% CI 1.10 to 2.40, p=0.02), the use of paclitaxel-eluting stent (PES) (OR=2.87, 95% CI 1.45 to 5.67, p<0.01), longer stent length (OR=1.07, 95% CI 1.01 to 1.13, p=0.03), smaller reference diameter (RD) before DES implantation (OR=0.44, 95% CI 0.19 to 0.99, p=0.04), smaller RD (OR=0.16, 95% CI 0.03 to 0.80, p=0.03) and minimum lumen diameter (MLD) (OR=0.03, 95% CI 0.01 to 0.28, p<0.01) after DES implantation. Multivariate parameters for predicting restenosis in the nondiabetic group were body mass index (OR = 1.32, 95% CI 1.05 to 1.66, p=0.02), A type of lesion (OR=0.11, 95% CI 0.02 to 0.53, p=0.01), the use of PES (OR=2.66, 95% CI 1.57 to 4.51, p<0.01), longer stent length (OR=1.06, 95% CI 1.01 to 1.11, p=0.02), smaller RD before DES implantation (OR=0.01, 95% CI 0.01 to 0.17, p<0.01), smaller RD (OR=0.36, 95% CI 0.16 to 0.80, p=0.01) and MLD (OR=0.01, 95% CI 0.01 to 0.08, p<0.01) after DES implantation. CONCLUSIONS: The use of PESs, high level of CRP, a small baseline and post-PCI vessel size, and longer stent length remained significant predictors of restenosis in both diabetes and nondiabetes even in the era of DES. The smoking and right coronary lesions were significant predictors of restenosis in diabetes while higher body mass index and A type of lesions were associated with restenosis in nondiabetes.