This paper presents a temperature and supply compensated sub-threshold voltage reference generator which generates a reference voltage of 173 mV at supply voltage of 0.6 V and temperature @ 27 °C, has been designed in 45 nm CMOS technology. Variation of output voltage with temperature over a range of -25 to 85 °C is 172.88 to 173.25 mV which gives temperature coefficient of 19 ppm/°C at supply voltage of 0.6 V. The variation of output voltage with supply over a range of 0.6 to 1.0 V is 173.20 to 173.85 mV which gives line sensitivity of 0.93 \%/V at temperature 27 °C. The simulated PSRR value of the proposed circuit is approx -55 dB till 1 MHz. © 2014 IEEE.