The reaction of labelled cholesterol with a large excess of freshly prepared 14-methylhexadecanoyl chloride in a simple glass apparatus was used for the synthesis of [3H]cholesteryl 14-methylhexadecanoate in microgram amounts. After purification of the crude product by thin-layer chromatography, the purity of the final preparation was better than 98% as checked by gas-liquid and high-pressure liquid chromatography. On average 90% of the input radioactivity was present in the ester. The same technique was also used for the preparation of [14C]cholesteryl 14-methylhexadecanoate and [3H] or [14C]cholesteryl laurate, myristate, palmitate, margarate and stearate with similar yields. All these preparations were found suitable for biochemical studies.