Canopy temperatures were measured on 50 exotic strains of cotton (Gossypium hirsutum) grown under irrigated and dryland conditions to evaluate whether differences existed between strains. Canopy temperatures were measured daily under clear sky conditions between 1330-1430 CST for a 35-day period with a handheld infrared thermometer. Canopy-air temperatures (Tc-Ta) differences for the dryland plots increased as the soil water was depleted from negative to positive values while in the irrigated plots Tc-Ta values were consistently negative. There were differences between strains within an irrigation treatment, and when combined over irrigation treatments showed that there were four classes of Tc-Ta response in each irrigation dryland comparison. These were cool- (irrigated) cool (dryland), cool-warm, warm-cool, and warm-warm, e.g., some strains attempted to maintain cool temperatures under increasing soil water depletion.