In this paper a low power consumption regulator has been proposed for ultra high frequency (UHF) RFID tag that has a stable output voltage. The sub-blocks of the regulator are supplied with the elementary stage output of the rectifier. The proposed operational amplifier (OPA) circuit works in class-AB and it is biased by an adaptive biasing circuit. Besides, in the proposed regulator the used bandgap reference (BGR) circuit and the sampling circuit are based on CMOS technology and they have low power consumption. The output of this regulator is 0.81 V that has +/- 1.5 mV ripple. The values of LIR. PSRR and the efficiency of the regulator are about 7.5 (mV/V), 42.5 dB and 53% respectively. Considering 10K Omega load, the power consumption of the regulator has been calculated as 147 W. The operating frequency is 960 MHz and it is simulated in TSMC 0.18 mu m CMOS technology. (C) 2014 Elsevier GmbH. All rights reserved.