Irrigation water is becoming scarce in irrigated potato production regions of the world. There is an urgent need to reduce the quantity of water needed to irrigate potato cultivars without sacrificing yield or quality. Field experiments were conducted 2016 and 2017 to investigate the effect of reduced irrigation water below ET recommendations and nitrogen (N) application rates on field performance of potato cultivar ‘Mesa russet’ in the San Luis Valley of Colorado. Treatments included three levels of irrigation (100, 90, and 65% of ET) and two levels of nitrogen (123 and 157 kg N ha-1). Treatments were factorially arranged in a randomized complete block design, with four replications. The treatments were, 1) 65% ET, 123 kg N ha-1 (Irri1N1), 2) 65% ET, 157 kg N ha-1 (Irri1N2), 3) 90% ET, 123 kg N ha-1 (Irri2N1), 4) 90% ET, 157 kg N ha-1 (Irri2N2), 5) 100% ET, 123 kg N ha-1 (Irri3N1) and 6) 100% ET, 157 kg N ha-1 (Irri3N2). Irri2N1, Irri2N2, and Irri3N1 produced higher and similar total and marketable tuber yields, compared to all other treatments in both years. Tuber bulking rate increased by 12.2 and 7.2 g/d for Irri1N1 and Irri2N1, respectively, from 103 to 113 days after planting, when compared to all other treatments in 2016. In 2017, early tuber bulking was observed in Irri3N1. However, tuber bulking rate was higher from 111 to 118 DAP for Irri3N2 (30.3 g/d) compared to all other treatments. Leaf area index was at a maximum for Irri3N2. During late tuber bulking, petiole N and K concentrations increased with the lowest irrigation 65% ET. The results indicate that reducing irrigation by 10% of normal ET with low N rate application can produce maximum tuber yield with high tuber bulking rate at late tuber bulking in potato cultivar ‘Mesa Russet’.