Patients with diabetes mellitus have worse outcomes after percutaneous coronary intervention than patients without diabetes mellitus. We compared the risk of stent thrombosis, myocardial infarction, death, and target lesion revascularization in diabetic and nondiabetic patients after implantation of drug-eluting stents or bare metal stents. In the Western Denmark Heart Registry, 12,347 consecutive patients (1,575 with and 10,772 without diabetes) were identified and followed up for 2 years. The 2-year risk of definite stent thrombosis was 0.52% in patients with diabetes mellitus and 0.71% in nondiabetic patients (adjusted relative risk RR 0.74, 95% confidence interval CI 0.41 to 1.34, p = 0.321). The 2-year risk of myocardial infarction was greater in the diabetic patients (6.9%) than in the nondiabetic patients (3.6%; adjusted RR 1.96, 95% CI 1.58 to 2.43; p <0.001). The all-cause 2-year mortality rate was almost twice as great for the diabetic patients compared to the nondiabetic patients (12.4% vs 6.7%; adjusted RR 1.91, 95% CI 1.63 to 2.23; p <0.001). The 2-year risk of target lesion revascularization was 8.5% in the diabetic patients and 6.8% in the nondiabetic patients (adjusted RR 1.28, 95% CI 1.10 to 1.49; p <0.001). In conclusion, 2 years after drug-eluting stent or bare metal stent implantation, diabetic patients had a greater risk than nondiabetic patients of myocardial infarction and death. Drug-eluting stent treatment reduced the risk of target lesion revascularization compared to bare metal stent treatment, regardless of diabetes status.