In the millimeter-wave band, the parasitic capacitances of MOSFETs cause degradation of the frequency bandwidth and the conversion gain of an up-conversion mixer. To improve the performance of an up-conversion mixer, we presents an up-conversion mixer with cross-coupled capacitors adopted in the local-oscillator (LO) input ports The cross-coupled capacitors cancel out the gate-to-drain capacitances of nMOSFETs for the LO input. It is verified by simulations that the bandwidth and the conversion gain are improved. The proposed mixer is fabricated by using a 180-nm CMOS process. It is shown that the proposed mixer has the-3 dB bandwidth of 5.9 GHz and the conversion gain of-8.2 dB. This work demonstrates the possibility of realizing 60-GHz transceivers in a mature, low-cost process.