Abstract The nearly unlimited enzymatic potential of cultured plant cells can basically be employed for bioconversion purposes. Plant enzymes are able to catalyze regio- and stereospecific reactions and can therefore be applied to the production of compounds of pharmaceutical interest. Naturally occurring as well as related synthetic compounds may be used as precursors. A review of the current status of such bioconversions is given. It includes the performance of bioconversions by freely suspended and immobilized plant cells or enzyme preparations. In addition, the kinetic aspects of immobilized plant cells are discussed. Special attention is paid to the bioconversion of poorly or water insoluble precursors. Finally, a model scheme for the development of a commercially available drug, produced by bioconversion, and perspectives are discussed.