In this paper, we present a 60-GHz single-balanced CMOS down-conversion mixer. The proposed mixer uses an on-chip active balun to furnish a differential output from an injected single-ended local oscillator (LO) signal. The millimeter-wave (mm-wave) active balun incorporates a cascode cross-coupled structure to generate the differential LO with a high voltage gain and minimum amplitude and phase mismatch. The overall mixer achieves a high conversion gain (CG) with a linearity and noise-figure performance that compare favorably with those of state-of-the-art designs. As a proof-of-concept, a 60-GHz mixer with a center intermediate-frequency (IF) of 20 GHz and output bandwidth of 3.2 GHz is designed and implemented in a 65-nm CMOS process. Measurement results show that the mixer achieves a peak conversion gain of 12.1 dB and 1-dB compression point of -5 dBm. Furthermore, the fabricated mixer achieves a minimum double-sideband (DSB) noise figure of 6.5 dB over the bandwidth of interest. The chip consumes 11.5 mW from a 1-V supply and excluding the pads occupies 0.27 mm² of silicon area.