One band switchable low noise amplifier (LNA) is designed for wideband applications. The proposed band switchable LNA has two switchable bands. The design consists of a input matching circuit, two cascode common-source amplifiers and an output buffer for measurement. The proposed LNA is designed with two switching capacitors as loading that use NMOS to make high quality factor. The proposed LNA gives switchable gains of 10.8dB and 16.8dB, and noise figure of 3.6-6.2dB and 3.1-6.5dB at 3.255.6GHz and 6-10.4GHz frequency band, respectively, while consuming 22.46mW through a 1.8V power supply using the TSMC 0.18μm CMOS technology.