OBJECTIVES: We compared the risk of stent thrombosis (ST) after drug-eluting stents (DES) versus bare-metal stents (BMS), and tested the hypothesis that the risk of DES thrombosis is related to stent length. BACKGROUND: Whether DES increase the risk of ST remains unclear. Given the very low restenosis rate after drug-eluting stenting, longer stents are frequently implanted for the same lesion length in comparison to BMS. METHODS: We included in a meta-analysis 10 randomized studies comparing DES and BMS. Overall, 5,030 patients were included (2,602 were allocated to DES and 2,428 to BMS). The risk of thrombosis after DES versus BMS was compared, and the relationship between the rate of DES thrombosis and stent length was evaluated. RESULTS: Incidence of ST was not increased in patients receiving DES (0.58% vs. 0.54% for BMS; odds ratio: 1.05; 95% confidence interval [CI]: 0.51 to 2.15; p = 1.000). The overall rate of ST did not differ significantly between patients receiving sirolimus- or paclitaxel-eluting stents (0.57% vs. 0.58%; p = 1.000). We found a significant relation between the rate of ST and the stented length (Y = -1.455 + 0.121 X; 95% CI for beta: 0.014 to 0.227; R = 0.716; p = 0.031). In patients with DES, mean stented length was longer in those suffering ST (23.4 +/- 8.1 mm vs. 21.3 +/- 4.1 mm, p = 0.025). CONCLUSIONS: Drug-eluting stents do not increase the risk of ST, at least under appropriate anti-platelet therapy. The risk of ST after DES implantation is related to stent length.