The advent of high yielding, early-maturing cotton (Gossypium hirsutum L.) cultivars and the increased use of nitrogen in cotton management has lead to the appearance of widespread potassium deficiencies. Field research was conducted at two locations in Arkansas in 1989 and 1990 to evaluate the beneficial aspects of foliar-applied potassium nitrate (KNO3) to cotton yield and fiber quality. Visible injury of leaves was not observed at foliar rates of 0, 3, 5, 10, 15, and 20 kg KNO₃ ha^-1. Petiole analysis indicated that plants receiving foliar applications of KNO₃ had significantly higher potassium concentrations than did the controls. Yield improvements were observed when plants were fertilized with both soil- and foliar-applied KNO₃, or foliar-applied KNO₃ alone, when compared to controls receiving no KNO₃ fertilizer. Fiber quality was significantly increased by foliar-applied KNO₃ in 1989 but not in 1990. The increase in 1989 occurred primarily in fiber uniformity and strength. Foliar applications of KNO₃ may be a useful cotton production practice for supplementing preplant soil applications of potassium fertilizer.