Cotton (Gossypium hirsutum L.) is a plant of tropical origin that is planted throughout the world for fiber production. Once planted it may be subjected to several environmental constraints like water stress, low and high temperatures, and nutrient shortage, conditions under which growth is affected and final yield reduced. Over the years, use of plant growth regulators in cotton production has been practiced. However, much of the work has been directed toward controlling growth rather than trying to enhance it. In the last 10 years industry has placed considerable emphasis on identifying chemical products that enhance cotton growth, especially when conditions are unfavorable. PGR-IV, a relatively new plant growth regulator, has been evaluated in cotton under a wide range of environmental conditions.