Putrescine, spermidine, and spermine were three main polyamines isolated from soybeans and partially characterized. Occurrence of polyamines in soybeans was established by separating trichloroacetic acid extracts of soybeans by cationic exchange column chromatography, identification with thin layer chromatography, paper electrophoresis, mass spectral analysis, reactions with ninhydrin and Dragendorff reagents, and spectrophotometric characteristics. Soybeans contained a minimum of 29.0 micrograms of polyamines per gram of full-fat flour. The alcohol-soluble fraction of soybeans contained polyamines also. Resting seeds contained spermidine in higher concentration than either putrescine or spermine. Spermine appeared to be present in lowest concentration. Preliminary experiments suggested that some polyamines were possibly in bound forms.