Effect of spermine on the phytochelatins (PCs) in cadmium-treated roots of Canavalia lineata seedlings was studied. With the treatment of spermine, total nonprotein thiol (SH) contents decreased by 55% in roots of Cd-treated plants. Glutathione (GSH) synthetase activity was inhibitied by 36.8% in roots and cysteine synthase was also inhibited by 9.5% while ${gamma}$-GluCys synthetase activity was not affected. From the PC-Cd complex analyses by gel column chromatography, it was found that Cd+spermine-treated roots contain an additional PC that has low affinity for Cd, in addition to Cd-induced PC whose SH:Cd ratio is 1:1. Spermine affected the PC concentration and composition in the Cd-treated roots of C. lineata seedlings.