Enzyme-catalyzed reactions are widely used at the laboratory or industrial scale whereas whole-cells-catalyzed reactions have been commonly restricted to special cases. The tremendous advances in genomics, proteomics, directed evolution, and metabolic engineering in the past few years have opened the door to the creation of tailor-made microorganisms for industrial purposes, which means a myriad of new possibilities for biocatalysis. The main goals of using whole cells as biocatalysts compared to enzymes are (1) whole-cell catalysts can be much more readily and inexpensively prepared than enzymes, and (2) enzymes - inside cells - are protected from the external environment and they are stabilized by the intracellular medium. In general, three defined scenarios have been considered where whole-cell-catalyzed processes may present advantages over the free-enzyme-catalyzed ones: (1) the required enzyme is intracellular; (2) the enzyme needs a cofactor to carry out the catalytic act, and (3) the goal depends on a multienzymatic process. In this article, several biotransformations of interest, namely, stereoselective reductions, hydroxylations of arenes or unfunctionalized alkanes, monooxygenations, halogenations, nucleoside synthesis, synthesis of glycosidic bonds, among others, as well as, the actual state of whole-cell-catalyzed biotransformations at the laboratory (milligrams), preparative (grams), or industrial scale (kilograms) are presented.