Pleurotus florida was transformed by complementation of auxotrophic mutant using chimeric plasmid containing Flammulina velutipes leu 2 gene and pBR 322 replicon. Mycelial morphology of transformants was grown and compared on mushroom complete and minimal medium. Transformants were mated with monokaryon and their genetic recombination was investigated for the morphology of fruitbody and spore analysis. $Leu^+$ transformant showed same mating type of $A_1B_1$ as to the untransformed mutant. The transformant and the untransformed mutant were mated with monokaryon of which mating type is $A_2B_1$, respectively. Although fruitbody of the untransformed mutant was not produced, $leu^+$ transformant produced fruitbody. Spore analysis showed that leucine requiring spores from fruitbody of $leu^+$ transformant were diminished when compared with those of untransformed mutant.