Drought is a severe environmental stress that limits agricultural production. Vegetable crops, including potato, have high water requirements and in most countries full or supplemental irrigation is necessary for successful vegetable production. However, water availability for agriculture is being reduced as a consequence of global climate change, environmental pollution and growing demand for other uses. Therefore, great emphasis is placed on crop management for dry conditions with the aim of increasing water use efficiency. To see how restricted irrigation systems affect water use efficiency and yield of potato, an experiment was conducted in an arid area in coastal Peru at the International Potato Center in Lima. Partial Root-Zone Drying (PRD), an innovative irrigation system in which both halves of the root system are alternately dried and well watered, was compared to conventional irrigation (CI) on an early potato cultivar (4 months) grown in furrows in randomized plots. Plants were fully and uniformly irrigated for 60 days following planting (pre-experimental period) and then treatments were applied up to the harvest time. For CI every furrow was irrigated during each watering. The PRD system consisted of alternately irrigating one of the two neighboring furrows during consecutive watering. CI and PRD were further divided into two treatments with different watering amounts, resulting in a total of four irrigation treatments, ranging from CI1 with 100% of the water typically applied to the potato crop in Lima, according to crop requirements; CI1/2 (50% of the amount of water applied to CI1); PRD1 (same amount of water as CI1/2); and PRD1/2 that received half of the water applied to PRD1. Fresh tuber yield was significantly higher for CI1 (45.1 t ha-1), followed by PRD1 (36.2 t ha-1), CI1/2 (33.9 t.ha-1) and PRD1/2 (31.0 t.ha-1). Water use efficiency (WUE) calculated for total water use (pre-experimental and experimental periods) was similar for PRD1/2 (2.6 kg DM ha-1. m-3), PRD1 (2.4 kg DMha-1. m-3), CI1 (2.3 kg DM.ha-1. m-3), and CI1/2 (2.2 kg DM.ha-1. m-3). However, WUE calculated for water used during the experimental period showed larger differences as it was higher for PRD1/2 (14.6 kg DM ha-1 m-3) followed by PRD1 (8.1 kg DM ha-1 m-3), CI1/2 (7.5 kg DM ha-1 m-3), and CI1 (4.9 kg DM ha-1 m-3). Our results suggest that the PRD irrigation system might become an alternative in large potato-producing areas in the world, where water is limiting and where salinity might become a problem.