Background/Aims: Chronic renal failure is associated with elevated indices of oxidative stress. We tested the hypothesis that the in vivo formation of the F₂-isoprostane (8-iso-prostaglandin PGF_2α), a bioactive product of arachidonic acid peroxidation, is enhanced in end-stage renal disease (ESRD) patients receiving hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD). Methods: Plasma samples were obtained from 35 HD patients, 30 CAPD patients and 30 age- and sex-matched healthy subjects for measurement of immunoreactive 8-iso-PGF_2α. Results: Plasma 8-iso-PGF_2α levels were significantly higher (p < 0.001) in HD and CAPD patients (346.3 ± 132.4 pg/ml; range 49.8–870) than in age-matched control subjects (150.9 ± 61.6 pg/ml; range 33.5–235). In addition, we also found that 8-iso-PGF_2α concentration was significantly (p = 0.007) higher in HD patients (389.8 ± 148.3 pg/ml) than in CAPD patients (254.3 ± 76.6 pg/ml). Plasma 8-iso-PGF_2α concentration was linearly correlated with serum haptoglobin, C-reactive protein (CRP) and plasma MDA (r = 0.58, p = 0.003; r = 0.29, p < 0.05 and r = 0.38, p < 0.05 respectively). On the other hand, plasma 8-iso-PGF_2α levels were inversely associated with serum albumin and total cholesterol (r = –0.31 and r = –0.28, respectively; p < 0.05). Conclusions: We conclude that ESRD on both HD and CAPD is associated with increased formation of F₂-isoprostanes, a correlate of enhanced lipid peroxidation. We also found that plasma 8-iso-PGF_2α was casually related to some acute phase reactant proteins such as serum CRP, albumin and haptoglobin. This may provide an important biochemical link between lipid peroxidation, inflammation and accelerated atherosclerosis in the uremic milieu.