Oxidized low-density lipoprotein (oxLDL) plays a crucial role in the development of atherosclerosis, however, the predictive value of circulating oxLDL for cardiac events (CE) in patients with coronary artery disease (CAD) has remained poorly understood. We prospectively studied 238 consecutive patients with documented CAD for up to 52 months until the occurrence of one of the following cardiac events: cardiac death, nonfatal myocardial infarction (MI), and refractory angina requiring revascularization. The plasma levels of oxLDL were measured by an enzyme-linked immunosorbent assay (ELISA) using the monoclonal antibody, DLH3. The levels of circulating oxLDL were significantly higher in patients with CE than in patients without CE (median 20.3 U/ml versus 17.6 U/ml, P = 0.002). Multivariate Cox models showed that higher level of oxLDL was an independent predictor of developing CE. The adjusted hazard ratios for CE were 3.15 (95% CI 1.47-6.76, P = 0.003) times higher in patients with the highest quartile of oxLDL levels and 1.88 (95% CI 0.90-3.95, P = 0.09) times higher in patients with the third quartile than in those within the lowest quartile. Thus, measurement of circulating oxLDL may be helpful in the assessment of future CE in patients with CAD.