Treatment of in-stent restenosis is generally considered low risk, and it is not clear if adjunctive use of abciximab is beneficial in this low-risk population. We determined the effect of adjunctive abciximab during percutaneous coronary intervention (PCI) for treatment of in-stent restenosis. Two hundred and ninety-three patients with in-stent restenosis underwent PCI at the Cleveland Clinic between January 1996 and December 1998. Patients undergoing directional atherectomy, laser treatment and brachytherapy were excluded (9 patients). Of the remaining 284, seventy-nine patients received abciximab during PCI and 205 were treated without abciximab. The groups were similar with respect to age, gender, left ventricular function, number of vessels involved, history of prior coronary artery bypass grafting and unstable symptoms at presentation. There were more diabetics, hypertensives, and patients with elevated cholesterol in the abciximab-treated group. At 1-year follow-up, there was a significantly lower incidence of myocardial infarction (2.5% versus 5.3%; p < 0.05) and lower mortality (1.2% versus 5.8%; p < 0.01) in the abciximab-treated group. There was no difference in the incidence of revascularization. The findings of a lowered mortality and myocardial infarction rate with abciximab warrants further prospective study in patients with in-stent restenosis.