The dyeing properties of cationic cotton dyed with acid dyes are examined ill this Study. For comparison, nylon 6 and untreated cotton are dyed by the same acid dyes (Sandolan Red MF-2BL, Sandolan Golden Yellow MF-GL, and Sandolan Blue MF-GL). A cationic agent, polyepichlorohydrin-dimethylamine (PECH-amine), is used to modify cotton fabric. Significant increase in color yield is observed for cationic cotton over untreated cotton because of the introduced positively charged sites by cationic modification. Deeper shades are obtained in all cases with cationic cotton. All of the acid dyes used in this study show significant hooking behavior with both cationic cotton and nylon. (c) 2006 Wiley Periodicals, Inc.