This critical review presents an introduction to biocatalysis for synthetic chemists. Advances in biocatalysis of the past 5 years illustrate the breadth of applications for these powerful and selective catalysts in conducting key reaction steps. Asymmetric synthesis of value-added targets and other reaction types are covered, with an emphasis on pharmaceutical intermediates and bulk chemicals. Resources of interest for the non-initiated are provided, including specialized websites and service providers to facilitate identification of suitable biocatalysts, as well as references to recent volumes and reviews for more detailed biocatalytic procedures. Challenges related to the application of biocatalysts are discussed, including how ‘green’ a biocatalytic reaction may be, and trends in biocatalyst improvement through enzyme engineering are presented (152 references).