Modern maize hybrid breeding is also focused on increasing nitrogen use efficiency (NUE) for grain production. The objectives of this study were to assess popcorn inbred lines for NUE, assess its genetic diversity for NUE and related traits, and investigate the relationship between vegetative and adult traits with NUE, under contrasting N levels. Nineteen inbreds were assessed for NUE and related traits under two contrasting N levels in a 2-year experiment, using complete blocks with three replications. Path analysis was performed using the vegetative N uptake and utilization efficiency and two root traits and four adult traits. The inbred 05-388 was the most efficient in N use under both N levels. The inbreds with higher N use and utilization efficiency, grain N content and post-silking N uptake were allocated in the same cluster in both N conditions. Leaf chlorophyll content and post-silking uptake can serve as target traits for identifying superior inbred lines for NUE. Vegetative N uptake and utilization efficiency, and total root length can be used for early selection of superior NUE inbreds. K E Y W O R D Sabiotic stress, leaf chlorophyll content, N dynamic, nitrogen use efficiency, root traits