Fermentation of sitosterol by a Pseudomonas species (SK-25) resulted in the formation of 5-stigmastene-3 beta, 7 alpha-diol; 5,6 alpha-epoxy-5 alpha-stigmastan-3 beta-ol; 5,6 beta-epoxy-5 beta-stigmastan-3 beta-ol and 5 alpha-stigmastan-3 beta, 5,6 beta-triol. The metabolites were characterized by a variety of conventional chemical and spectrometric techniques.