A differential CMOS rectifier with a dynamic body-biasing technique is proposed for high-sensitivity RF energy harvesting (RFEH) applications. The dynamic body-biasing technique increases the forward current in the charging period and decreases the reverse current in the discharging period. Consequently, the charging speed is improved, and the input power range over which a high power conversion efficiency (PCE) can be obtained is broadened. A prototype device is fabricated in 90-nm CMOS technology with an active area of 0.16 × 0.16 mm2. The device is shown to operate at 900 MHz and to have a high sensitivity of −23.4/−19.3 dBm at a 1-V output voltage and 1/0.2 MΩ resistive loads. Moreover, a maximum PCE of 44.8% is obtained at an input power of −17.9 dBm under the resistive load of 0.2 MΩ. Notably, the rectifier maintains a high PCE (> 20%) over a wide input power range of 14.3 dB.