Adequate availability of water and nitrogen (N) is important for production of high potato yields of high processing quality tubers.  In this study, “Ranger Russet” potato cultivar was grown in a Quincy fine sand (mixed, mesic, Xeric Torripsamments) with Center Pivot irrigation in Columbia Basin production region in the Pacific Northwest (PNW).  Treatments included: (1) two soil water regimes after the row closure, i.e. irrigations to replenish either full ET (I1) or 70% of ET (I2, Deficit irrigation);  (2) four pre-plant N rates, i.e. either 0, 56, 112, or 168 kg N/ha; (3) three in-season N rates, i.e. either 112, 224, or 336 kg N/ha.  The in-season N was applied with pivot irrigation in five doses at 4, 6, 8, 10, and 12 weeks after seedling emergence.  The cumulative ET during the growing season was 713 mm.  The cumulative irrigation amounts were 790 and 580 mm, respectively, for the full ET and deficit irrigation treatments.  The combination of pre-plant and in-season N treatments resulted in a range of total N rates from 112 to 504 kg N/ha.  During the peak plant growth, the total N in the plants (including the tubers) were 283, 464, and 423 kg/ha for the 168, 336, and 504 kg N/ha treatments, respectively.  Therefore, N mineralized form previous crop residues contributed to the total N in the plants at the low N rate, while there was considerable loss of N at the high N rate treatment.  Total tuber yield was 24 percent lower for the deficit irrigation treatment (66 Mg/ha) as compared to that for the Full ET irrigation treatment (87.3 Mg/ha).  The proportion of the total tuber yield in the large size class (>340 g/tuber) was greater for the latter as compared to that for the former irrigation treatment.