Abstract: A method of increasing the amount of mineral filler which can be contained in filled paper sheet produced on a papermaking machine without consequentially reducing the mechanical properties such as the tensile strength of the paper sheet comprises incorporating the mineral filler into the paper pulp furnish, before the latter is transferred to the wire, in the form of a filler/polymer conglomerate formed by contacting the mineral filler with a relatively high molecular weight polymer having a zeta potential in the range of from -40 to +40 electron volts.