The Texas High Plains and adjacent Rolling Plains represents the largest contiguous cotton production area in the U.S. Yields are fairly low due to lack of an adequate water supply throughout the growing season across the entire region. The second major limitation is a short growing season, especially on the Southern High Plains. Narrow row production systems have the potential to increase yields in marginal environments by increasing fruit production and retention and rate of boll development through increased light interception. However, the potential for greater water use rates also exists. In a water deficit environment, this could create more problems than it resolves. Experiments were conducted over a 6 year period (1983-1988) to compare 30 with 40 inch row spacing across a range of water supplies using two different soil textures. The results indicated a consistent yield advantage ranging from 9% under dryland conditions to 18% under irrigated conditions for the 30 inch row spacing over the 40 inch rows. The major yield component responsible for the yield increase was more mature bolls/acre. Narrow rows had a greater rate of production of fruiting sites and a greater retention of early fruit. Total water use was not different between 30 and 40 inch rows. The amount of water lost to free soil evaporation was greater with the 40 inch rows. Narrow row cotton production systems offer a definite advantage over traditional 40 inch rows even in marginal environments.