The phenolic acid derivatives genistein, daidzein, and coumestrol have been identified for the first time in unhydrolyzed soybean (Glycine max "Wells II") root extracts. High-pressure liquid chromatography (HPLC) was used to separate and isolate eluant fractions from dimethyl sulfoxide (DMSO) extracts of fresh soybean roots. The eluant fractions were concentrated by freeze drying, then subjected to ultraviolet (UV) and gas chromatography-mass spectroscopy (GC-MS) analysis for positive identification of each compound. The UV spectra of the compounds in methanol were observed from 200 to 450 nm. The GC-MS analysis included both direct probe analysis of the crystals and analysis of their trimethylsilyl (TMS) derivatives.