Transformation of Schizosaccharomyces pombe with DNA requires the conditioning of cells to promote DNA uptake followed by cell growth under conditions that select and maintain the plasmid or integration event. The three main methodologies are electroporation, treatment with lithium cations, and transformation of protoplasts. The protocol for protoplast transformation, which is described here, is more complicated than those for electroporation or lithium acetate and thus less often used. However, for some strains, it remains the only reliable protocol.