Electrostatic discharge (ESD) protection design for high-linearity single-pole double-throw (SPDT) transmit/receive switch (T/R switch) at 0.9/1.8 GHz GSM band was proposed and verified in a standard 0.18-μm CMOS process. The SPDT CMOS T/R switch was implemented with body-floating technique, multi-stacked structure, and series-shunt topology to obtain low insertion loss, high power handling capability, and good isolation. With the proposed ESD protection design, the T/R switch can sustain human-body-model (HBM) ESD voltages of 3.5 kV under the positive-to-V_SS stress and 5 kV under the negative-to-V_SS stress. Experimental results including ESD characteristics, RF performance, and failure analysis are presented.