Studies were conducted in field 1993-1997 to evaluate the effect of new and existing plant growth regulators (PGRs) on growth, yield and physiology of field-grown cotton (Gossypium hirsutum L.). Treatments consisted of an untreated control and the following PGRs: Atonik, Crop⁺², CCC, Cytokin, Early Harvest (EH), Maxon, MepPlus, Mepiquant Chloride (MC), PGR-IV, and PHCA. Most PGRs tested could influence plant growth and numerically increase lint yield. However, results have varied with season. Studies have also been conducted on the physiological effect of PGRs on cotton growth and yield, and are discussed in this paper. These results provide a data base for producers to use in the selection of PGR use in cotton management.