This paper illustrates a methodology to design an ultra-low power hybrid bandgap reference (HBR) with high accuracy to counteract the effect of temperature using single BJT and MOSFETs working in subthreshold region. Based on compensated VBE and ΔVth, the study provides a new insight into compensation of complementary-to-absolute-temperature (CTAT) voltage with a nano-watt proportional-to-absolute-temperature (PTAT) voltage generator with reduced threshold voltage-induced process variation. Designed in a 180 nm CMOS process, the circuit has a measured temperature coefficient of 26.2 ppm/°C with a wide temperature range of −40 °C∼125 °C and an overall variation coefficient of 0.234% among 9 chips with an active area of 0.0264 mm2. The experimental result shows that the proposed HBR circuit can operate with a supply voltage down to 1.1 V and a full frequency PSRR of better than −35 dB while the power consumption is only 6.435 nW.