**1. Introduction**

The genus *Phalaenopsis* consists of approximately 60 species and the various traits of hybrids are due to easy interspecific and intergeneric crossing compared to other higher plants. Germination and propagation of *Phalaenopsis* in nature (or under natural conditions) are very difficult since their seeds contain no endosperm storing nutrients for germination. Therefore, "micropropagation" (mass proliferation) by aseptic culture technologies has been used for the research and industrial production of *Phalaenopsis* for a long time before. In recent years, molecular breeding by biotechnology has been extensively studied. In this chapter, we will review the latest knowledge of classification, proliferation methods, and molecular breeding of *Phalaenopsis* by biotechnology.
