Interactions between some dis-azo dyes, different by either the position of their sulfonic groups or their number (Ponceau SS, Crocein Scarlet MOO, Congo Red, and Direct Blue 1), and some strong polycations (PCs), with cationic centers in their side chains and dye removal from artificial wastewaters were systematically investigated in this study. PCs with variable charge densities (CDs) were prepared from poly(dimethylaminoethyl methacrylate) by controlled quaternization with benzyl chloride. Even when the main process in the dye removal was charge neutralization (coagulation) for all of the dyes, significant effects of the CD and dis-azo dye structure on the metachromatic behavior of the dyes in dilute aqueous solutions and on the dye removal efficiency were observed. The stability of the PC/azo dye complex and, connected with this, the flocculation window were higher when the PC with the highest CD was used. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 728-735, 2009