The objective of this work was to evaluate the capability of both seminal plasma and sperm cells to scavenge different forms of oxyradicals and the possible correlation with sperm motility parameters. A total of 14 individuals were analyzed by computer-assisted sperm analysis (CASA) and the results integrated with the measurement of total oxyradical scavenging capacity (TOSC) toward peroxyl radicals, hydroxyl radicals and peroxynitrite in seminal plasma and spermatozoa. TOSC values revealed some significant correlation with kinetic sperm cell parameters, including curvilinear velocity (VCL), straight-line velocity (VSL) and linearity (LIN). A lower antioxidant capacity toward hydroxyl radical was found in the seminal fluid of men with reduced sperm motility. Such correlations were not found with peroxyl radicals and peroxynitrite, neither when TOSC values were analyzed in spermatozoa. The TOSC assay is a useful tool for studying the relationship between oxyradical toxicity and abnormal sperm cell motility. Although further investigations are needed, the data clearly establish different role for various forms of oxyradicals, i.e., hydroxyl radicals, in altering sperm motility. Measurement of TOSC is suggested as a useful means of indicating relationship between reactive oxygen species and sperm cell kinetics in clinical trials and antioxidant-based treatments.