A multi-location study to evaluate the response of California Acala cotton varieties to applied N was conducted in the San Joaquin Valley from 1995 through 1999. The test plots included a range of soil types, production conditions, and levels of residual soil N. Soil NO₃-N was measured post-planting and post-harvest. Fertilizer N rates, 50, 100, 150 and 200 lbs N/acre, were applied prior to the first irrigation. Initial soil NO₃-N levels ranged from 30 to over 200 lbs N/acre. Across all locations and years, cotton lint yield increased significantly with each fertilizer increment up to 150 lbs N/acre. However, only 10 of the 31-site/year locations showed significant yield increases to added fertilizer. Soil NO₃-N in the surface 4 feet decreased from spring to post-harvest in all treatments. The lower fertilizer rate treatments utilized more soil NO₃-N than the higher rates. In 1996, a moderate yield year, soil NO₃-N averaged across all locations increased in the 4 - 8 foot depth for all N rates except for 50 lbs N/acre. In 1997 with higher yields, only the two higher N fertilizer rates had increased soil NO₃-N in the 4 - 8 foot depth. Residual soil NO₃-N from the previous crop can have a significant impact on N fertilizer utilization by the subsequent cotton crop and must be accounted for.