This paper presents the design of a 2-16 GHz ultra wide band low noise amplifier (UWB LNA). The proposed LNA as again of 11.5 ± 0.85 dB with NF less than 2.82 dB. Good input and output impedance matching, good isolation and linearity are achieved over the operating frequency band. The proposed UWB LNA consumes 18.14 mW of power from 1.8V supply. This UWB LNA is designed and simulated in 0.18 µm CMOS process.