Genetic transformation was first described by Griffith in 1928 and has since been demonstrated in a variety of organisms, including many species of fungi. This review focuses on the history and technology of the transformation of Saccharomyces cerevisiae. The application of protocols developed for S. cerevisiaeto other important yeast species is discussed. The protocols for transformation by spheroplasting, LiAc/ssDNA/PEG, and electroporation are compared, and possible mechanisms for transformation are discussed.