Constant demands always exist for producing something new in the market of ornamental crops. Therefore, it is important to broaden the genetic variability through the suitable and available breeding strategies for each target ornamental plant. In our laboratory, we have been trying to evaluate the usefulness of plant biotechnologies such as tissue culture, embryo rescue, protoplast fusion and genetic transformation as the means for broadening the genetic variability and for creating novel useful germplasm to the breeders of ornamental crops. So far, interspecific hybrids have been produced in the different groups of plants, such as Cosmos, Kalanchoe, Primula and Begonia with the aid of embryo rescue technique. Some of the products of these interspecific hybridizations have successfully been utilized to produce commercially available cultivars. Somatic hybrids have also been produced in Dianthus and Primula based on our successful establishment of plant regeneration systems from protoplasts. In our laboratory, genetic transformation systems have successfully been established in various ornamental crops, such as orchids (Phalaenopsis, Cymbidium, Dendrobium, Cattleya, Vanda), Nierembergia, Petunia, Lilium, Dahlia, Begonia, Primula and Mattiola. By utilizing these transformation systems, transgenic plants of useful traits, such as dwarf Phalaenopsis, insect-resistant Mattiola incana, blue Dahlia and blue Phalaenopsis have already been produced. Based on the results of these studies, prospective future on the application of plant biotechnology for the ornamental plant breeding will be described.