Aim of the study was to assess the clinical and angiographic efficacy of oral treatment with prednisone at immunosuppressive dosage after percutaneous coronary interventions (PCI) in patients with bifurcation lesions treated with elective bare metal stent (BMS) implantation in the main-branch (MB) and provisional stenting in the side-branch (SB). Twenty-five patients were treated on 29 bifurcation lesions (58 vessel segments). Lesion preparation before stenting was performed with atherectomy in 7 cases, and balloon PCI over double wires in all other cases; none was treated directly with stents. The mean length of stents implanted in the MB was 19.6 +/- 4.9 mm (10-30 mm). Balloon PCI was successful in 23 of 29 SB and provisional stenting was needed in 6 SB (21%). All patients received oral prednisone according to the immunosuppressive protocol previously reported (1 mg/kg/day/10 days, 0.5 mg/kg/day/20 days, 0.25 mg/kg/day/15 days). At 12 months, one patient had recurrence of angina (4%) and two patients underwent repeated target lesion revascularization (8%). No patient died or had stent thrombosis. Quantitative coronary analysis was performed in all patients at 8 months. Global restenosis rate per vessel was 8.6% (5/58), and 17.2% (5/29) per lesion. The restenosis rate and late lumen loss were 3.4% and 0.36 +/- 0.6 mm, and 13.8% and 0.47 +/- 0.46 mm in the MB and the SB, respectively. Single stent implantation in the MB and provisional stenting of the SB is feasible in most cases after adequate lesion preparation. The systemic treatment with oral prednisone after BMS implantation offers good clinical and angiographic results even in the difficult setting of bifurcation lesions.