The effects of annual broadcast, topsoil applications of muriate of potash (112 kg K₂O/ha/yr) to the same field plots on the development and yield of cotton was studied from 1986 through 1988. Higher levels of exchangeable K⁺ occurred each year in soil samples (0-8 inch depth) from potash treated plots application did not significantly (Pò 0.05) affect seedling survival, lint yield, lint percent, fiber elongation (E(1)) and micronaire, boll weight or flower counts. Foliar symptoms of Verticillium wilt significantly lower for plants grown in potash treated plots compared to the untreated control. Potash significantly increased seed index (weight of 100 seed) and fiber span length (2.5% and 50%) and strength (T(1)). Most of these parameters differed significantly between two cotton cultivars, (DES 119 and Stoneville 825). Except for wilt percent root-gall index, lint percent and seed index, the other parameters measured showed no significant potash x cultivar interaction.