Antioxidant properties of phenolic compounds, mainly tannins, present in red and brown bean seed coats were investigated. Polyphenols were extracted with 0.5% HCl in methanol, vacuum condensed and lyophilised. The amount of hydrolysing and condensed tannins, catechines and anthocyanins was evaluated in preparations. Antioxidant properties were measured against linoleic acid. The process of oxidation was monitored with a spectrophotometric method. All the preparations exhibited antioxidant activity. The brown bean preparation, which had the high tannin content (92%), was more effective as an antioxidant than red bean preparation.