This paper presents an automatic gain control (AGC) system suitable for 60GHz direct conversion receivers. By using a two step gain control algorithm with high-pass filter cutoff frequency switching, the proposed AGC system realizes fast settling time and wide dynamic range simultaneously. The paper also discusses wide-bandwidth variable gain amplifier (VGA) design. By introducing digitally-controlled resistors and gain flattening capacitors, the proposed VGA realizes wide gain range while compensating gain variations due to parasitic capacitance of MOS switches. The AGC system is implemented in a transceiver chipset where RFIC and BBIC are fabricated in 90nm CMOS and 40nm CMOS respectively. The measurement shows excellent dynamic range of 47dB with +/-1dB gain accuracy within 1µs settling time, which satisfies the stringent requirements of the IEEE802.11ad standard.