Oxidized low density lipoproteins (oLDL) play an important role in the pathogenesis of atherosclerosis. Recently, elevated oLDL autoantibodies in serum were shown in patients with severe peripheral atherosclerosis. To evaluate their role in restenosis after percutaneous transluminal coronary angioplasty (PTCA), oLDL autoantibodies were determined in a randomly selected series of 48 males following successful PTCA. Follow-up angiography as well as blood sampling were done 12 months after PTCA; restenosis was defined as ≧ 50% reduction in diameter of the coronary artery. Twenty-six patients (mean age: 56 years) showed restenosis (Restenosis Group), whereas 22 (mean age: 53 years) had open vessels (Patent Vessel Group). Both groups did not differ in age, past medical history, fibrinogen and lipid profile as well as in initial angiographic findings. Oxidized LDL autoantibodies were 13 ± 21 U in the Restenosis Group and 6 ± 4 U in the Patent Vessel Group, showing no significant difference. Six of 26 patients in the Restenosis Group and 3 of 22 in the Patent Vessel Group (NS) had elevated oLDL autoantibody levels ( > 10 U). Thus, although there is a trend to elevated oLDL autoantibodies in males with restenosis of coronary arteries, oLDL cannot serve as a strong marker for stenosis following PTCA.