In this paper, a noise-cancelling variable gain low noise amplifier (VG-LNA) is presented for ultra-wideband (UWB) applications. The proposed VG-LNA is designed for 3.5-9 GHz frequency bands using RF-TSMC CMOS technology. The proposed LNA employs a common gate input stage and a common source second stage while a noise cancellation technique is used to minimize the noise figure of the input stage. By utilizing a feedback loop at the second stage, the gain of the LNA is continuously controlled. Simulation results exhibit the flat power gains (S ₂₁ ) of 12 dB, noise figure (NF) of 3.4 dB and input return loss (S ₁₁ ) less than −10 dB over the wide bandwidth of 3.5 to 9 GHz. The linearity parameter of third order input intercept point (IIP3) is −10.5 dBm at 8GHz. The proposed VG-LNA has power dissipation of 11.9 mW under a 1.3 V.