A resistive feedback-based inductive source degeneration ultra-wideband (UWB) CMOS low noise amplifier (LNA) with floating n-well terminals has been proposed. The resistive feedback technique provides wideband input matching with a small amount of noise degradation by reducing the quality factor of the input resonant circuit. In addition, all n-wells terminals of the triple-well RF transistors are connected to the supply voltage through high value resistors in order to reduce unwanted parasitic capacitances, leading to improvement of the RF performance of the proposed LNA. The proposed UWB LNA is implemented in 0.13µm CMOS technology and all inductors are fully integrated in this work. Measurement results show a power gain of 10dB from 3GHz to 6GHz, a minimum (maximum) noise figure of 2.3dB (3.8dB), an input return loss of better than −8dB, and an input referred IP3 of −7dBm. The fabricated chip consumes only 5mA from a 1.5V supply voltage.