Simple model systems consisting of butter oil or refined cottonseed oil mixed with melted beeswax and its unsaponifiable components were designed to study hydrolytic and oxidative rancidity during storage. Whole beeswax at 0.5 and 1% (w/w) levels possessed significant pro-hydrolytic activity whilst its unsaponifiable components at 0.25 and 0.5% (w/w) exhibited an anti-hydrolytic effect on butter oil. The addition of whole beeswax at 0.5 and 1% caused no effect on the peroxide and thiobarbituric acid values of butter oil. However, beeswax unsaponifiable components significantly reduced both peroxide and thiobarbituric acid values of stored butter oil.