In this work, the effects of corona discharge (CD) and chitosan treatment on the dyeability of polyester/cotton blends with direct and reactive dyes were studied. The surface chemical changes of polyester and cotton were analyzed using X-ray Photoelectron Spectroscopy (XPS). The correlation between chemical changes, wettability, and dyeability after CD and/or chitosan treatment has been established. Color intensity of both single components and PES/cotton blend increased proportionally with increasing chitosan concentration. The results obtained open the possibility for a new method for dyeing of polyester/cotton blends in a single bath using one dye-class that is commonly used for dyeing of textile material of cellulosic origin.