The application of biologically derived catalysts to the synthesis of agrochemicals has become increasingly popular in recent years. In most cases, the aim of using a biotransformation is either to introduce chirality into the molecule, to achieve a regioselective functionalization, or to selectively convert a functional group among other groups with similar reactivity. Pheromones, which have recently been commercialized as agrochemicals, are generally used in enantiopure forms with their intentional mixtures. Since they are usually highly effective, only very small quantities are needed to achieve the desired activity. This review, with approximately 200 references covering the period previous to December 2004, describes various efficient means of preparing optically pure pheromones and their precursors with the aid of isolated enzymes and microorganisms serving as catalysts.