This paper presents a Ka-Hand BiCMOS trans-mint/receive (T/R) module with amplitude and phase control. In the receive mode, the 33-37 GHz T/R module results in a gain of 9-19 dB, a noise figure of 4-5 dB and an input P ldB of -29 dBm. In the transmit mode, the maximum gain and output PldB are 10 dB and +5.5 dBm, respectively, and can be controlled over a 10 dB range (output Psat is+8 dBm). The measured rms gain and phase errors are < 0.6 dB and < 7°, respectively, in both the transmit and receive modes. The chip is only 0.93×1.33 mm2 and consumes 58 mW and 29 mW in the transmit and receive modes, respectively. To our knowledge, this is the first Ka-Band BiCMOS T/R module to-date, and with applications in satellite communications and defense systems.