This letter presents a new architecture of merged low noise amplifier and mixer, which employs a noise cancellation scheme and uses an inductor as an inter-stage matching network between LNA and mixer to absorb parasitic capacitances. As the parasitic capacitances degrade the gain and noise figure of the entire circuit, using an inductor in the inter-stage can very effectively improve both noise figure and gain of the circuit. Based on this new method, a merged LNA-mixer has been designed in a 0.18-µm RF CMOS technology. Simulation results show 4-dB increase in power conversion gain and 1.7-dB improvement in noise figure in comparison with the case without inter-stage filter. This circuit draws only 5mA from a 1.8V supply and covers the frequency range of 1.3GHz to 4.1GHz. Its large bandwidth as well as low power consumption makes it suitable for rapidly growing software defined radio RF transceivers.