The use of GaAs FETs as microwave switches is discussed, and the feasibility of such devices for applications requiring ultra low dc power consumption, low insertion loss, and bidirectionality is demonstrated. A discrete SPST switch consisting of two parallel-resonated single-gate GaAs FETs exhibited 0.5 db insertion loss with 25 db isolation at 8.5 GHz. The first monolithic SPDT switch incorporating parallel-resonated GaAs FETs is also reported.