Late-season K deficiency in cotton (Gossypium spp.) is becoming more widespread. The objective of this research was to determine the effects of K rate and placement on cotton nutrition, yield, and quality. Fertilizer K treatments included 0, 60, 120, and 180 lb K/acre broadcast and incorporated, 0, 30, 60, and 90 lb K/acre banded in a 4" x 4" proximity to the seed, and combined broadcast/band treatments at 60/30, 60/60, 120/30, and 120/60 lb K/acre. The source of K was KCl (0-0-60) for all treatments. Parameters measured in this study include leaf K and Mg at early bloom, dry matter yield and total K uptake at early boll maturation, soil exchangeable K, and lint yield and quality. Consistent increases in leaf K were found for broadcast and band K treatments. Combined K treatments compared favorably with broadcasting and banding except at the 180 lb K/acre rate which had significantly less leaf K than 180 lb K/acre broadcast. Leaf Mg decreased with increasing K rate when broadcast, but not when banded. Combined K treatments resulted in the lowest leaf Mg levels except at the rate of 180 lb K/acre. Fertilizer K rate or method of application did not influence dry matter production or lint quality. Broadcast application of K resulted in increased K uptake with increasing rates, while a consistent trend was not apparent for banding or combined treatments. Broadcast applications of K resulted in increased lint yield up to 120 lb/acre, after which it declined. Lint yield increased with up to 60 lb K/acre banded, after which it declined. The combined treatments resulted in the greatest lint yield increases. Lint yield increased with increasing combined rate up to 150 lb K/acre. Lint yield decreased at the combined rate of 180 lb K/acre and was no different than broadcasting K at this rate. Soil exchangeable K levels were influenced the most by broadcast application of K for both sampled depths.