Odontotermes formosanus (Shiraki) and O. hainanensis (Light) (Isoptera: Termitidae) are two dominant termite species that damage earthen dikes in China. This paper describes behavioral biology (mating, egg caring, hatching, and molting) and development of incipient colonies of these two species under laboratory conditions. Oviposition of O. formosanus and O. hainanensis began 8–11 d and 2–5 d after mating, respectively. The eggs of both species were laid in batches. Egg hatching of O. formosanus and O. hainanensis required assistance from parents or nestmates. Average hatching periods of these two species were 31 d and 27 d, respectively. The molting process of O. formosanus and O. hainanensis also required help from nestmates. Such assistance was more essential for O. hainanensis than for O. formosanus. Average developmental times from newly hatched O. formosanus to adult workers and to soldiers were 16.7 d and 23.8 d, respectively. For O. hainanensis, these times were 18.1 d and 19.6 d, respectively. The survival rate of the incipient colonies of O. formosanus at 6 mo after establishment was below 50%. Colony death probably was due to unsuccessful culture of the fungus, Termitosphaeria duthiei.