Yield potential of cotton varieties has long been one of the determining factors to variety selection. Growers have recently begun to look closer at their variety selections to reflect cotton varieties that will perform at a consistent level year in and year out. Stability regression analysis of varieties performance over several years can give a very strong indication of how a variety will withstand variations in growing conditions. Two environmental regimes were separated for comparison purposes. Varieties were evaluated in an irrigated and non-irrigated comparison as well as in a conventional versus reduced- tillage system. A comparison was made for four Delta and Pine Land Company varieties commonly grown in the northern Mid-South Delta region. Linear regression equations were calculated for PM 1218 BG/RR, DP 451 B/RR, DP 436 RR, and Sure-Grow 747. The R² value was used to describe the scatter in a variety yield compared to the mean of all varieties from low to high yield environments. High R² indicates low variation from the average response of all varieties across environments. DP 451 B/RR and DP 436 RR had the least amount of variation from the trial mean with respect to yield, fiber length, fiber strength, and micronaire. These varieties were determined to be the most stable under normal cotton growing conditions with very little difference from the trial mean. Sure-Grow 747 has a higher yield potential, and also had high R²- values, slightly lower than DP 436 RR and DP 451 B/RR in the irrigated and conventional tillage comparison. The R² of PM 1218 BG/RR for yield appeared to be lower than the other varieties, however, PM 1218 BG/RR has higher yield potential as indicated by a greater slope in irrigated and conventional tillage tests. Risk-averse growers should tend to want more acreage planted to a variety such as DP 451 B/RR, where as high input growers that set a goal for maximum yield might plant more high yielding varieties such as PM 1218 BG/RR.