Recent occlusion of aortocoronary venous bypass grafts had occurred in three patients, aged between 64 and 67 years. In all three recanalization was achieved after 8 hours, two and five days, respectively, of coronary angioplasty combined with local urokinase infusion for 24 hours. The procedure consisted of passing a guide-wire through the occluded bypass graft, the tip of the wire then being advanced to the periphery of the native coronary artery. The balloon was then repeatedly dilated along the length of the graft. Primary opening was not achieved in one of the grafts, and the other two closed again, despite repeated and prolonged balloon dilatation. In all three patients a coronary infusion catheter was then placed into the graft lumen and urokinase (3 mill. units) infused over 24 hours. An angiogram 24 hours later demonstrated an open bypass graft (residual stenosis < 50%). Angiography 9 to 14 weeks later revealed restenosis in one case, but it was reopened by balloon dilatation and stent insertion, while the other two had remained open without significant stenosis.