The effects of early-season foliar applications of the gibberellic acid-based plant growth regulator Ryzup on growth and yield of upland cotton were evaluated in Corpus Christi and Uvalde, Texas during 1996 and 1997. Ryzup was applied at a rate of 4 oz/acre broadcast as follows: once at the 3rd to 5th true leaf stage, once at the 5th to 7th true leaf stage, and twice at the 3rd to 5th and at the 5th to 7th true leaf stages. Growth and yield responses to Ryzup varied between years and locations within a range of ±20% of UTC. Mixed results did not indicate any best treatment of Ryzup regarding timing or number of applications. Growth responses to Ryzup application appeared to be inversely related to cumulative atmospheric water demand during the 30 days following treatment.