The present invention relates to a process for producing a dispersion of white fine particles from which a white ink that is capable of exhibiting excellent hiding power, rub fastness and 
water resistance even when printed on a low-water absorbing printing medium can be obtained by incorporating the dispersion of the white fine particles into the ink, and a water-based ink for ink-jet printing which contains the white fine particles. The present invention provides [1] a process for producing a dispersion of white fine particles, including step 1 of mixing 
titanium oxide and a 
polymer dispersant at a pH value that is not less than an acid dissociation exponent (pKa) of at least a part of an acid component of the 
polymer dispersant to thereby obtain a 
titanium oxide dispersion, in which an 
isoelectric point (A) of the 
titanium oxide and the acid dissociation exponent (pKa) (B) of the 
polymer dispersant satisfy a relationship represented by the formula: A−B≥0, the polymer dispersant contains a constitutional unit derived from a 
hydrophobic monomer, and a volume median particle size (D50) of particles in the 
titanium oxide dispersion is from 150 to 500 nm; and step 2 of adding a polymerizable 
monomer to the 
titanium oxide dispersion obtained in the step 1 to subject the polymerizable 
monomer to 
polymerization reaction, thereby obtaining the dispersion of the white fine particles, and [2] a water-based ink for ink-jet printing which contains the white fine particles obtained above.