(24R and 24S)-5beta-cholestane-3alpha,7alpha,24,25-tetrols were prepared by osmium tetroxide oxidation of 5beta-cholest-24-ene-3alpha,7alpha-diol. The resulting diastereomeric tetrols were separated by thin-layer chromatography, their purity ascertained by melting point, gas-liquid chromatography and mass spectra and their structural configurations were assigned by molecular rotation measurement and circular dichroism studies. In a similar fashion, the (24R and 24S)-5beta-cholestane-3alpha,24,25-triols were prepared and their structures identified.