A synthesized cationic reagent named polyamide-epichlorohydrin (PAE) was used to cationize cotton fabrics which were dyed with nanoscale pigments after PAE modification. The results showed that when the PAE concentration was below 7% (owf), the K/S value increased nearly linearly with increasing of PAE concentration, and excess that concentration the K/S value did not increase further. With increasing the pH value of cationization bath, the K/S value increased first and then decreased, the maximum K/S value appeared at pH 9-10. Cotton fabrics cationized at 80 degrees C for 20 mm exhibited the best cationizing result. Both the pigment uptake and the color strength reached their own maximum values when the dye bath was neutral. When the pigment concentration was 1% (owf) the addition of 1g/L sodium chloride in the dye bath could decrease the pigment uptake while for 5% (owf) pigment concentration the uptake increased with increasing the amount of sodium chloride. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 2736-2742, 2010