The importance of adequate crop nutrition in producing high cotton yields and good quality fiber is recognized. The purpose of this paper is to review the basis for properly monitoring cotton nutrient status in relation to fertilizer management. We have limited our discussion to nitrogen (N), because of its major role in plant metabolism and its constant need for replenishment in today's cotton production systems. For N, an efficient fertilizer management program relies on proper and regular use of monitoring with a combination of soil and plant tissue testing. The program should be implemented on a field by field basis with farmers establishing realistic target yields to determine the crop's total fertility requirements. Soil tests must be an integral component and used to estimate mineral and organic N available to the crop before fertilizer is applied. Plant testing for petiole nitrate or leaf total N should be used during the most critical flowering period as a means of responding rapidly to dynamic changes caused from weather and soil related factors. Crop simulation models, like GOSSYM-COMAX, can provide an additional tool to assess N utilization and predict the future crop needs to meet the projected target yield.