The effect of obesity on repeat coronary revascularization and restenosis in patients who undergo stent implantation has not been reported. We therefore examined the database from the multicenter randomized TAXUS-IV trial to determine the effect of body mass index (BMI) on outcomes after bare-metal and drug-eluting stent implantation. In TAXUS-IV, patients were randomized to receive a slow-release, polymer-based, paclitaxel-eluting stent or a bare-metal stent. Outcomes were stratified by baseline BMI. Of the 1,307 randomized patients who had documented BMI, 233 (17.8%) had normal weight (BMI <25 kg/m2), 531 (40.6%) were overweight (BMI < or =25 to 30 kg/m2), and 543 (41.5%) were obese (BMI > or =30 kg/m2). Patients who had been assigned to receive bare-metal stents and were overweight and obese compared with those who had normal weight had higher rates of 9-month binary restenosis (29.2% and 30.5% vs 9.3%, respectively; p = 0.01) and 1-year major adverse cardiac events (20.8% and 23.2% vs 11.1%, respectively; p = 0.02), whereas rates of these events did not differ significantly among those who received a paclitaxel-eluting stent (7.6% and 9.3% vs 4.9%, respectively for binary restenosis; p = 0.65; 11.3% and 10.4% vs 10.1%, respectively; p = 0.82 for major adverse cardiac events). By multivariate analysis, BMI > or =30.0 kg/m2 independently predicted binary restenosis (hazard ratio 4.26, p = 0.005), 1-year target vessel revascularization (hazard ratio 1.95, p = 0.04), and major adverse cardiac events (hazard ratio 1.95, p = 0.004) in patients who received bare-metal stents but not paclitaxel-eluting stents. In conclusion, obesity is an important risk factor for clinical and angiographic restenosis and for composite major adverse cardiac events in patients who receive bare-metal stents. Paclitaxel-eluting stents attenuate the increased risk associated with obesity, such that the intermediate-term prognosis after percutaneous coronary intervention is independent of weight.