A complete treatment of the thermal noise in a MOSFET including both drain current noise and induced gate current noise has been developed by deriving a small-signal model valid at high frequencies and for short-channel devices. On the basis Of this model the parameters currently used for the representation of a noisy two-port have been derived. As those parameters depend on the noise sources and on the admittance matrix terms, both these: contributions have been accurately modeled. Finally, the model has been applied to the derivation of MOSFET two-port noise parameters in order to minimize noise figure of low noise amplifiers.