The improvement in Nitrogen use efficiency is a key issue for sustainable and profitable cropping systems. Agronomic practices and genotypes variability can affect NUE. The Nitrogen utilization efficiency (NUEg), a component of Nitrogen use efficiency, represents the amount of grain produced per unit of absorbed N. Agronomic practices can affect NUEg in a similar way than dry matter partitioning, since they are closely associated. The objective of this study was to evaluate the relationships among NUEg and its components. Experiments (Exp) were carried out in INTA Paraná Research Station (Argentina, 31º 50S; 60º 31W). Exp 1 and 2 were sown in optimal planting dates and included 3 planting densities (6.5, 8.5 y 10.5 plants m^-2), Exp 3 included 3 hybrids (dent, semi-dent, and flint). In Exp 4 and 5, treatments were a combination of hybrids and planting dates. Crops were conducted under non limiting water and N conditions. Grain yield (g), shoot biomass (B) at maturity and its N concentration, were used to calculate several NUEg components: harvest index (HI), N harvest index (NHI) and cumulative N in stover (NS). NUEg was positively correlated with HI and NHI and negatively correlated with grain N concentration (GNC) and NS. Although GNC has been suggested as an index of NUEg, our results showed no differences due to planting densities (Exp 1 and 2) and among hybrids (Exp 3, 4 and 5). NHI was negatively correlated to NS and positively to HI, suggesting that crop ability to remobilize N is critical to improve NUEg. Differences in NUEg were not related to changes in GNC, therefore HI and NHI could be more valuable indexes to select superior genotypes in the physiological ability to use N.