There is limited research on the resolution for corn (Zea mays L.) grain yield estimation using optical sensor technology. Yield prediction based N management has economic and environmental benefits. The objective of this study was to determine the optimum resolution for prediction of corn grain yield using sensor based technology. Corn rows, 30 m in length, were randomly selected at three locations where the exact location of each plant was determined. A GreenSeeker optical sensor unit was used to determine average NDVI for 1 to 15, 20, 25, and 30 plants and the average NDVI over fixed distances (0.2, 0.4, 0.6, 0.8, 1.0, 0.46, 0.91, and 2.7 m). Individual corn plants were harvested and grain yield was determined. Correlation of corn grain yield versus NDVI was evaluated over increasing distances and increasing number of plants. Coefficient of determination (R2) were maximized (NDVI versus Grain yield) when NDVI and grain yield were analyzed over every 5 plants. Similarly when correlation was evaluated for NDVI versus grain yield, R2's were highest when both were averaged over fixed distance of 1 m.