Continuous-wave high-power green light generation at room temperature is reported in a single-pass frequency-doubling configuration with bulk periodically poled MgO:LiNbO3 crystal placed outside a diode end-pumped Nd:GdVO4 laser. The MgO:LiNbO3 samples of 6.95-microm domain period, uniform periodicity, and 50% duty cycle along the entire crystal length are fabricated by use of a high-voltage multipulse poling method. A maximum power of 1.18 W at 531 nm with 16.8% conversion efficiency is obtained from a 2-mm-thick, 25-mm-long MgO:LiNbO3 crystal; the corresponding internal green power and conversion efficiency are 1.38 W and 19.6%, respectively, whereas the normalized conversion efficiency is 3.3%/W.