In this paper, a concurrent dual-band folded-cascode mixer with a dual-band LC-tank biasing circuit is presented. The operation frequency bands of the dual-band mixer are around 2.3GHz and 5.2GHz, respectively. A topology of LC series-parallel resonance, which is located on the current-sinking path of the biasing circuit is used to arrive at a dual-band characteristic. An on-chip balun is designed to transform a single-ended signal, such as a radio-frequency input signal and a local oscillation signal, into a couple of differential signals for the presented mixer. The simulated/measured conversion gains are about 15.6dB/13.4dB and 11.3dB/8.6dB at 2.3GHz and 5.2GHz, respectively. The measured IIP3 is −6.7dBm and −1.1dBm at 2.3GHz and 5.2GHz, respectively. The RF reflection coefficients at both bands are below −8dB. The measured single sideband noise factors, NF SSB , are about 12.1dB and 16dB at 2.3GHz and 5.2GHz, respectively. The DC power consumption of the core circuit is 7.52mW under 1.6V supply voltage.