4-Diphosphocytidyl-2C-methyl-D-erythritol serves as an intermediate in the nonmevalonate pathwayof isoprenoid biosynthesis. The compound has been prepared in millimole quantity by a sequence of one-potreactions using 13C-labeled pyruvate and dihydroxyacetone phosphate or 13C-labeled glucose as starting materialsand recombinant enzymes of the nonmevalonate isoprenoid pathway as catalysts. The method has been usedfor the preparation of various 4-diphosphocytidyl-2C-methyl-D-erythritol isotopomers in high yield.