en Original Article Original Article - Background: It has been proposed that oxidative stress plays an important role in male infertility. The aims of this study were to compare seminal plasma levels of 15-F2t-isoprostane (8-iso-PGF2?), malondialdehyde (MDA), and total (sum of free and bound) homocysteine (tHcy) in normozoospermic vs. asthenozoospermic men, and to examine the relationships between tHcy and lipid peroxidation products. Materials and Methods: The study was a case-control study with a simple random sampling. The case group consisted of 15 asthenozoospermic males. This group was compared with 15 normozoospermic men. Seminal plasma levels of 15-F2t-isoprostane and tHcy were measured using commercially available enzyme immunoassay (EIA) kits. MDA levels were determined by the thiobarbituric acid (TBA) assay. The Mann-Whitney U test was used to compare two groups. Coefficients of correlation were calculated using Spearman&rsquo;s correlation analysis. All hypothesis tests were two-tailed with statistical significance assessed at the p value <0.05 level. Results: MDA levels were lower in asthenozoospermic subjects than in control subjects (0.72&plusmn;0.06 &micro;M vs. 0.40&plusmn;0.06 &micro;M; p<0.05). No differences were seen in 15-F2t-isoprostane levels in asthenozoospermic subjects and controls (65.00&plusmn;3.20 pg/ml vs. 58.17&plusmn;4.12 pg/ml; p>0.05). Interestingly, tHcy levels were slightly higher in asthenozoospermic subjects than in controls (6.18&plusmn;1.17 &micro;M vs. 4.8&plusmn;0.52&micro;M). Sperm motility was inversely correlated with seminal plasma 15-F2t-isoprostane and MDA levels, respectively (p<0.05). Conclusion: Seminal plasma levels of 15-F2t-isoprostane and tHcy showed no significant differences between normozoospermic and asthenozoospermic men. Sperm motility correlated inversely with seminal plasma levels of 15-F2t-isoprostane and MDA. No relationship was found between tHcy and lipid peroxidation. However, higher sample size is required to confirm these findings. Seminal Plasma, 15-F2t-Isoprostane, Malondialdehyde, Homocysteine, Lipid Peroxidation, Asthenozoospermia, Normozoospermia 34 39 http://ijrm.ir/browse.php?a_code=A-10-100-19&slc_lang=en&sid=1 Nosratollah Zarghami Yes Ali Khosrowbeygi No