Abstract: Partial submergence promotes rapid internodal growth in deepwater rice (Oryza sativa L.), and this is regulated by three plant hormones: ethylene, gibberellin and abscisic acid. GA is the immediate hormonal signal for this growth response. Ethylene renders the internode more responsive to GA by lowering the level of endogenous abscisic acid. The rapid internodal elongation is related to osmoregulation, the cell wall composition, such as expansins of deepwater rice internodes. Some suggestions on the further research on deepwater rice are given.