The five Rhododendron cultivars, America , Catawbiense grandiflorum roseum , Madame Carvalho , Mars and Nova Zembla were used for transformation by Agrobacterium tumefaciens carrying T-DNA with the gusA gene encoding β-glucuronidase (GUS) gene and the neomycin phosphotransferase II gene as a selectable marker gene. The GUS reporter gene was successfully transferred into all five cultivars as indicated by fluorimetric staining, polymerase chain reaction (PCR) and Southern blot analysis. Some primary transformants appeared to be chimeric as both GUS expression and GUS nucleotide sequences were lost during vegetative propagation.