The efficient use of fertilizer N remains an important goal in maximizing yield of maize (Zea mays L.). Our objective was to characterize the response of grain yield and nitrogen use efficiency (NUE) to fertilizer N rate in a wide range of commercial and experimental hybrids, and then use this information to develop strategies for improving NUE or its components. An array of 42 commercial and 238 experimental hybrids, selected to represent the genetic range in maize, were grown under various N levels (varying from deficient 0 kg N/ha up to excessive 340 kg N/ha) between 2001 and 2005, and plant and grain samples taken at physiological maturity to determine NUE and its principle components, uptake and utilization efficiencies. Because the hybrids differed in the N level they required for maximum yield, and because NUE and its components declined with increasing N rates, we calculated each individual hybrid’s NUE at the N rate that just optimized grain yield. Commercial hybrids had a higher average optimal NUE than the genetic range hybrids (17.3 vs. 14.4 kg kg/N), but a narrower range (difference of 29 vs. 42 kg kg/N). The commercial hybrids were substantially better in N uptake than the genetic range material (average optimum of 50% compared to 34%), but were lower in N utilization (33.5 vs. 40.7 kg kg/N). The maximum uptake and utilization values observed within the hybrid ranges shows that no hybrid was optimized for both N use components, and suggests room for improvement in the NUE of maize.