AbstractThe use of mineral fillers in cellulosic paper products can result in cost/energy savings and improvement of paper properties. However, the increase in filler addition levels is hampered by the negative impact of fillers on paper strength, poor filler retention, etc. As an attempt to improve the use of fillers in papermaking, filler modification with the combination of cationic starch and carboxymethyl cellulose was preliminarily explored in this mini-study. This concept was compared with filler modification with either cationic starch or carboxymethyl cellulose. The combination of cationic starch with carboxymethyl cellulose resulted in improved attachment of the starch to the filler, possibly suggesting the in-situ formation of polymer complexes with lower solubility than starch. With respect to filler retention, tensile strength, brightness, and opacity of the filled paper, the combined use of cationic starch and carboxymethyl cellulose resulted in a modified filler material with modestly better performance, in comparison to filler modification with either cationic starch or carboxymethyl cellulose. The combined use of a cationic polymer and an anionic polymer to modify fillers may provide an alternative approach to improving the use of mineral fillers in the paper industry.