Sugarcane is the most important row-crop in Louisiana.� Currently, determining recommended N-rate for sugarcane in Louisiana is usually based on crop age and soil type.� In-season environmental conditions not a factor in determining recommended N-rates.� Therefore, over or under application of N fertilizers is an ever-present potential risk.� The objective of this study was to determine the relationship between an in-season vegetative response index (RI) using normalized difference vegetative index (NDVI) and the response of sugarcane yield.� The study was evaluated on six site years between 2008 and 2010, in southern Louisiana.� Each trial received varying amounts of fertilizer N and was evaluated over four different varieties.� Sensor readings were taken two weeks after N fertilization using a GreenSeeker� handheld sensor for four sampling times with two weeks interval,.� Traditional means to determine RI, i.e. comparing only a non-limiting N plot to a check plot, posed a limitation in terms of number of data points in the model.� A modified RI calculation was used to determine both in-season and harvest RI.� This modified RI compared all N rates to the check plot to obtain a RI for all applied N rates.� The modified in-season RI shows potential at predicting sugarcane yield response to fertilizer N; with coefficient of determination value of 0.91 and 0.86 for cane yield and sugar yield, respectively.� In summary, NDVI collected early in the season can be used to predict the sugarcane yield response to fertilizer N.