The mobilization of food reserves and the subcellur localization of lipoxygenase-1 and -2 were studied in the cotyledons of germinating soybean seeds (Glycine max (L.) variety AmSoy and A(,5)) and seedlings. When germination begins, the cotyledon tissues are packed with protein and lipid bodies. Mobilization of these reserves started in the epidermis and vascular bundles. After three days of germination, significant reductions of protein and lipid bodies were observed; concurrently the number of starch grains, glyoxysomes, and mitochondria were increased. These structural changes will be discussed with reference to the metabolism of the cotyledons;Density gradient fractionation and immunogold labelling studies showed that lipoxygenase-1 and -2 are localized in the cytoplasm of storage parenchyma and epidermal cells from day 1 up to 7. However, in vascular bundle cells of three-day-old seedling, few gold labels were seen in protein bodies. No association was found with mitochondria, lipid bodies, endoplasmic reticulum, or other organelles. No difference in subcellular distribution of the isozymes of lipoxygenase was observed between variety AmSoy and genetic mutant A(,5).