One approach for reducing the contribution of potato (Solanum tuberosum L.) production to nitrate contamination of groundwater is to develop cultivars which utilize N more efficiently. In this study, variation in N use efficiency (NUE; dry matter production per unit crop N supply) characteristics of 20 commercial potato cultivars of North American and European origin were evaluated in 2 yr. Cultivars were grown with or without application of 100 kg N ha-1 as ammonium nitrate banded at planting. The recommended within-row spacing was used for each cultivar and no irrigation was applied. Plant dry matter and N accumulation were determined prior to significant leaf senescence. Crop N supply was estimated as fertilizer N applied plus soil inorganic N measured at planting plus apparent net soil N mineralization. Nitrogen use efficiency decreased curvilinearly with increasing crop N supply. Nitrogen use efficiency was lower for early-maturing cultivars compared to mid-season and late-maturing cultivars. A curvilinear relationship was obtained between plant dry matter accumulation and plant N accumulation using data for all cultivars. Deviations from this relationship were interpreted as variation in N utilization efficiency (NUtE; dry matter accumulation per unit N accumulation). Significant differences in NUtE were measured among cultivars of similar maturity. Nitrogen uptake efficiency (NUpE; plant N content per unit crop N supply) and soil nitrate concentration measured at plant harvest were uniformly low for all cultivars when crop N supply was limited, but varied among cultivars when N was more abundant. This suggests that potato cultivars vary more in terms of N uptake capacity (plant N accumulation in the presence of an abundant N supply) than in terms of NUpE. Key words: Solanum tuberosum, N mineralization, dry matter accumulation, N accumulation, N utilization efficiency