Starting from cholesterol a simple and efficient synthesis of 5 alpha-cholestane-3,6-dione and 5 beta-cholestane-3,6-dione is described. The 13C shielding data of C-7, C-9, and C-19 in both isomers can be used in the determination of the stereochemistry at C-5 of these compounds. The combination of 13C NMR spectroscopy and the simple synthesis of both isomers offers good opportunities for the determination of the stereochemistry at C-5 of 3,6-dioxosteroids.