Four sterol-inhibiting fungicides were evaluated for efficacy against southwestern cotton rust caused by Puccinia cacabata Arth. & Holw. on upland cotton (Gossypium hirsutum L.) and pima cotton (G. barbadense L.) in 1990 and 1991. Efficacy was highest for Summitt 25DF (triadimenol), intermediate for Folicur 3.6F (terbutrazole) and Tilt 2E (propiconazole) and lowest for Bayleton 5ODF (triadimenol). Spray date in relation to time of infection had more effect on disease than number of sprays or rates.