The neomycin phosphotransferase II gene (nptII) was introduced into geranium (Pelargonium zonale hybrids) protoplast by using PEG or electroporation method. The presence of the introduced DNA in the protoplast and the expressions of the gene in the transformed cells were examined. The presence of the nptII DNA in the protoplasts were detected by polymerase chain reaction. The expressions of nptII gene in the transformed cells were confirmed by the nptII assay.