A five-year study conducted across the major cotton production regions of Texas showed that cotton lint yield at only 8 of 39 sites, or about 20%, responded positively to the addition of supplemental fertilizer N. Below normal rainfall contributed to lowered response in some years, but the major contributing factor appeared to be high amounts of residual soil NO3. Amounts greater than 100 lbs of residual NO3-N/acre were found in 22 of the 39 profiles sampled. Results indicated that where residual NO3-N was greater than 100 lbs N/acre to a depth of three or four feet, lint response to N fertilization was minimal. The quantity of soil NO3 above which no response to fertilizer N may be expected may be even lower for dryland locations where water is limiting. Annual soil testing for NO3 to a depth of 24 inches will improve fertilizer N recommendations, increase crop yields, quality and production economics, and be more protective of the environment.