90 nm Si-CMOS high power handling Transmit/Receive (T/R) Switch is proposed for 60 GHz wireless applications. By adopting series and shunt FETs circuit configuration and by employing large FET gate width of 320 μm, high transmit power handling capability is achieved. Since the use of large FET gate width degrades the insertion loss and isolation in the receive mode, a microstrip line is connected between the source and drain to make resonance with Coff of the FET at 60 GHz in off-state. Simulated result shows that the designed T/R switch has over 1 W transmit power handling capability at 60 GHz. Fabricated results show the linear transfer characteristics up to 24.8 dBm at 60 GHz and 36.5 dBm at 36 GHz in transmit mode. Both upper limits comes from the limitation of measurement setup and we expect that this T/R switch has over 1 W power handling at 60 GHz.