The ?Styrian-Oil-Pumpkin?(Cucurbita pepo subsp. pepo var. styriaca) is one of the mostimportant crop plants in Styria and the Styrian pumpkin seed oil is made of its seeds. Inthis study the concentrations of the antioxidants glutathione and ascorbate, the glutathioneprecursor cysteine and the activity of glutathion-reductase were analysed inleaves and seeds by using HPLC and photometry. One week old cotyledons showed ahigher concentration of cysteine than one week old true leaves, but older cotyledonsshowed a lower concentration of cysteine compared to one week old cotyledons andolder leaves showed a higher concentration compared to one week old true leaves. Theconcentrations of glutathione and ascorbate were lower in older cotyledons and leavesthan in younger and the decrease of the concentration of ascorbate was much fasterthan the decrease of the concentration of glutathione. In older seeds the concentration ofcysteine was higher than in younger seeds, but there was nearly no change in the concentrationof glutathione; ascorbate could not be detected. The activity of the glutathionereductasewas found in seeds, but not in all leaves. Its activity was lower in older seedsthan in younger.