This paper presents a reconfigurable multi-band class E power amplifier designed in CMOS technology. The proposed class E power amplifier operates efficiently over sparsely separated frequency bands by switching the capacitance of the load network. Simulation results showed a stable and high power added efficiency of 60% with 18.5 dB gain, and 83% with 14.5 dB gain for 2.4 GHz and 5 GHz WLAN applications, respectively.