The report reviews the theory of cotton fiber drying and cotton drying response to various conditions as determined by laboratory research. Commercial seedcotton drying systems design and performance are discussed as well as how drying can affect fiber quality. Some basic characteristics of two relatively new seedcotton drying systems are presented with some discussion of their differences from current tower drying systems. A brief summary of current USDA drying research and the effects of drying on cleaning completes the review.