Summary Low molecular weight antioxidants (LMWAs) were assayed by square wave voltammetry (SWV) using screen printed electrodes. Standard antioxidants, i.e. uric acid, ascorbic acid, trolox and glutathione, were assayed in order to estimate the sensitivity and standard redox potentials of individual LMWAs. In another experiment, plasma from Grey Partridges was used as model real samples. Ferric reducing antioxidant power (FRAP) was used as a reference method. Two peaks in plasma samples were found by SWV and correlated to FRAP. The SWV peaks were successfully correlated to FRAP. The practical importance of SWV carried out on screen printed electrodes is discussed.