Technical Abstract: Adding nitrogen (N) fertilizer to growing crops is preferable to adding excessive amounts before planting. This is because early season precipitation in the Midwest and Eastern states frequently exceeds crop needs. Excess water either results in nitrate leaching or runoff. Center-pivot irrigation systems and high-clearance sprayers now make it possible to apply N fertilizer to corn at any growth stage. Environmental stewardship goals encourage producers to reduce early season fertilizer N application rates and add more during the growing season if needed. Knowing when and where to apply fertilizer N during the growing season is the challenge to producers. This study evaluated several remote sensing techniques to determine crop N status of corn during the growing season. The green and red components of color displayed in an aerial photograph were highly correlated with grain yield. Placing a specific filter over the camera lens makes it possible to generate a black-and-white photograph with gray-tones that are indicative of crop greenness. These techniques make it possible to identify areas within a field that are likely to be N deficient. Field scouting can easily verify these observations and aid in making management decisions.