We have developed a stable, DNA-mediated transformation system for the white-rot basidiomycete Trametes versicolor based on the dominant selectable marker shble (phleomycin resistance). We employed a vector containing the selectable marker under control of expression sequences from the basidiomycete Schizophyllum commune and a polyethylene glycol/CaCl2, protoplast-fusion technique to introduce the transforming DNA. This transformation system generated stable phleomycin-resistant transformants at a frequency of four to seven transformants/mug of transforming, DNA.