With the increasing cost of fertilizer N, there is a renewed emphasis on developing new technologies for quantifying in-season N requirements for corn. The objectives of this research are (i) to evaluate different vegetative indices derived from an active reflectance sensor in estimating in-season N requirements for corn, and (ii) to consider the influence of N:Corn price ratio on the economic optimum N rate (EONR) developed using these indices. Field experiments were conducted at eight site-years in central Pennsylvania. A two-way factorial experiment was implemented as a split-plot randomized complete block (four blocks) design, with different N sources applied at planting as the main plot factor and NH4NO3 applied at V6 (NV6) as the sub-plot factor to measure yield response to NV6. Canopy reflectance measurements were obtained using a Crop Circle (Holland Scientific, Lincoln, NE) sensor just before NV6 applications. The EONR at V6 at 6:1 price ratio ranged from 0 to 221 kg ha-1 with a mean of 69 kg ha-1. Better prediction of EONR was obtained by indices calculated relative to a high N plot than absolute indices. Relative Green Difference Normalized Vegetation Index (RGNDVI) was the best predictor of EONR at V6 when expressed as linear-plateau model with an r2 of 0.79. Results indicate that the EONR estimates derived using the Crop Circle sensor need to be adjusted based on the current N:Corn price ratio. For a given value of RGNDVI, the EONR estimate is higher at lower price ratio and vice versa.