Starch, sodium oleate, and calcium chloride were used for the modification of calcium carbonate filler, so that the negative impact of filler addition on paper strength can be reduced by surface encapsulation with cellulose-bondable starch/oleic acid complexes. The impact of filler modification process conditions and retention systems was evaluated based on the filler bondability factor (in terms of tensile strength), filler retention, and tensile strength/brightness/opacity of filled paper. Noticeably, at the filler addition level of 20%, filler modification resulted in an increase in filler bondability factor of about 130%. The use of cationic polyacrylamide or polyacrylamide/bentonite resulted in an increase in retention of modified filler in paper-sheets from 57.3% to 72.3% or 76.4%. The filler bondability factor was also improved by using these two retention systems.