Hydrogen sulfide (H(2)S) is among a family of endogenous molecules of gas, defined as gasotransmitters. In recent years, endogenous production of H(2)S and its physiological importance have been realized. Abnormal metabolism and functions of H(2)S contribute to or participate in the pathogenesis of many diseases. This article reviews recent discoveries on the roles of H(2)S in the regulation of cell proliferation and apoptosis. The molecular mechanisms for the cellular effects of H(2)S are also recapitulated, including changes in mitogen-activated protein kinase, cell cycle-related kinase, cell death-related gene and ion channels. A better understanding of H(2)S-regualted cell growth or death will pave way for future design of novel pharmacological and therapeutic interventions for various diseases.