Early studies of a cobalt-based alloy stent coated with the novel antiproliferative agent zotarolimus and a phosphorylcholine polymer have demonstrated significant reductions in angiographic restenosis and target vessel revascularization compared with bare metal stents. However, the generalizability of the angiographic outcomes and clinical benefit of zotarolimus-eluting stents (ZESs) to a more real-world patient population is undetermined. Clinical and angiographic outcomes in 1,317 patients treated with the ZES in the first 4 trials of the Endeavor ZES (Medtronic Vascular, Santa Rosa, CA) clinical trials program were pooled for systematic analysis. Protocol-specified follow-up angiography was performed at 8 or 12 months for a subset of 750 of these patients, and clinical follow-up was performed at 9 months after the index procedures in all patients. Diabetes mellitus was present in 22.5% of patients, the mean reference vessel diameter was 2.73 mm, and the mean lesion length was 14.59 mm. At 8 months (12 months for ENDEAVOR I), mean +/- SD in-stent late luminal loss was 0.61 +/- 0.49 mm. In-stent late luminal loss was greatest in larger caliber (>2.9 mm) vessels (0.65 +/- 0.49 mm) and longer (>16.3 mm) lesions (0.70 +/- 0.52 mm) but did not statistically vary according to diabetic status. At 9 months, overall rates of target lesion revascularization (TLR) and major adverse cardiac events (MACE) were 4.9% and 7.7%, respectively. The rate of TLR at 12 months was not significantly different relative to diabetes and lesion length >16.3 mm (7.2% and 7.7%, respectively), although TLR was significantly more common when reference vessel diameter was <2.5 mm (8.5%; p = 0.013). At 24 months, overall rates of TLR and MACE were 6.5% and 9.9%, respectively. The overall 24-month rate of stent thrombosis was 0.3%, with no events occurring >14 days after the procedure. Despite varied clinical and angiographic characteristics, treatment with the ZES is associated with consistently low rates of TLR and overall major adverse events, including stent thrombosis. Although these findings indicate the efficacy and safety of the ZES over the time course of the first 4 ENDEAVOR clinical trials, additional ongoing study with more open patient inclusion criteria (including long lesions, small vessels, bifurcations, etc) will be important for discerning whether comparable clinical outcomes can be extended to lesion subsets of higher complexity.