Abstract: Transgenic microorganisms that produce vanillin when provided with caffeic acid or an esterified or other derivative thereof are disclosed. The organisms are transformed with expressible nucleic acid sequences encoding (1) a 3-0-methyltransferase, preferably from a plant source, which converts caffeic acid to ferulic acid and (2) either a eukaryotic (preferably plant) non-oxidative chain-shortening enzyme or a bacterial CoA ligase and enoyl-CoA hydratase/lyase enzymatic system, either of which converts ferulic acid to vanillin. Methods of making vanillin in the transgenic microorganisms are also disclosed.