Methyl-d3bromide was easily converted by treatment with calcium iodide into methyl-d3iodide in 94% yield. The latter was reacted on the 50-millimole scale with silver acetate or silver acetate-d3to yield methyl-d3acetate or methyl-d3acetate-d3. Methyl iodide and silver acetate-d3gave methyl acetate-d3.