Cochineal dyeing was applied to natural fiber fabrics, cotton and silk fabrics, and synthetic fiber fabrics, nylon and polyester fabrics. Chitosan-pretreatment was applied to the fabrics in order to investigate the effect of chitosan treatment on the dyeing behavior. The effect of chitosan treatment on the mordanting was also investigated by incorporating Cu-mordant on the chitosan-treated or chitosan-untreated fabrics during the dyeing process.