We review the hot-carrier effects and reliability problem in MOSFET. The mechanisms that produce the substrate and gate current are discussed, and the various mechanisms for hot-carrier degradation are presented. DC and AC lifetime models are summarized, and the effects on a CMOS circuit explained. The effects of scaling on the hot-carrier induced degradation are presented and the influence of processing steps and stress temperature discussed. Ways to improve the reliability of MOSF̄ETs are then presented. Finally the reliability of SOI MOSFETs is compared to that of bulk MOSFETs.