The everolimus-eluting stent (EES) has been shown to significantly decrease neointimal proliferation at 6 months compared with the bare metal stent (BMS) in patients with de novo coronary lesions. We report mid-term outcomes based on different vessel sizes in the combined FUTURE I and II trials. In the prospective, randomized, FUTURE I trial (single center) and expanded FUTURE II trial (multicenter), 106 patients (107 lesions) were randomized to EESs (n = 49 lesions) or BMSs (n = 58 lesions). Patients were categorized into 3 groups based on preprocedure reference diameter as assessed by quantitative coronary angiography (small vessel < 2.75 mm, medium vessel 2.75 to 3.25 mm, and large vessel > 3.25 mm). At 6-month follow-up, EESs decreased in-stent late lumen loss (decreased rate range of 78% to 94%), resulting in significantly larger minimum lumen area as assessed by intravascular ultrasound (increased range of 34% to 42%) compared with the BMS across all vessel sizes. There were no cases of in-stent restenosis with EESs at any vessel size but 8 cases with BMSs (5 in small vessels). No stent thrombosis, aneurysm formation, or late stent incomplete apposition was observed in any group. The EES appears to be effective for treatment of de novo coronary lesions in decreasing neointimal proliferation at 6-month follow-up compared with BMSs, regardless of vessel size.