This paper has explored an ultra-low-power design of two 60-GHz direct-conversion receivers in a 65-nm CMOS process for single-channel and multi-channel applications under the IEEE 802.15.3c standard, respectively. One subthreshold biasing 0.4-V transconductance mixer is designed with a compact quadrature hybrid coupler (160 μm × 210 μm with measured 3-dB intrinsic loss) in receivers to achieve low power (8 mW for single channel and 12.4 mW for multi-channel) and high gain (55 dB for single channel and 62-dB for multi-channel). One three-stage low-noise amplifier employs high- Q passive matchings. A double-layer-stacked inductor is utilized for matching in the single-channel receiver and a high-impedance transmission line is utilized for matching in the multi-channel receiver, respectively. In addition, one new modified Cherry-Hooper amplifier is applied for the variable-gain amplifier design to achieve high gain-bandwidth product and high power efficiency. The single-channel receiver is implemented with 0.34- mm2 chip area. It is measured with a power consumption of 8 mW, a minimum single-sideband noise figure (NF) of 4.9 dB, a 3-dB bandwidth of 3.5 GHz, and a maximum conversion gain of 55 dB. The multi-channel receiver is implemented with 0.56- mm2 chip area. It is measured with a power consumption of 12.4 mW, a 3-dB bandwidth of 8 GHz (59.5 ~ 67.5 GHz), and a maximum conversion gain of 62 dB. The measurement results show that the two demonstrated 60-GHz direct-conversion receivers can achieve high gain and low NF with ultra-low power in 65-nm CMOS.