The present invention relates to a water-based ink for ink-jet printing which is excellent in rubbing resistance upon printing on coated papers such as photographic papers, and also exhibits a high optical density upon printing on plain papers. The water-based ink for ink-jet printing according to the present invention includes a dispersion of a pigment wherein the number of pigment-containing polymer particles in the pigment dispersion which have a particle size of 0.57 μm or more among the pigment-containing polymer particles contained in the pigment dispersion in the ink is 1.2×107/mL or less.