The present invention relates to [1] a water-based ink including pigment-containing water-insoluble polymer particles A, water-insoluble vinyl-based polymer particles B and an organic solvent C, in which the water-insoluble polymer particles A are obtained by crosslinking polymer particles; the water-insoluble polymer particles B include at least one material selected from the group consisting of water-insoluble vinyl-based polymer particles and the like; the organic solvent C includes at least one compound selected from the group consisting of diethylene glycol monobutyl ether and diethylene glycol monoisobutyl ether, and propylene glycol, in which a total content of diethylene glycol monobutyl ether and diethylene glycol monoisobutyl ether in the water-based ink is not less than 0.8% by mass, and a content of an organic solvent having a boiling point of higher than 250° C. in the water-based ink is not more than 5% by mass; and a content of water in the water-based ink is not less than 45% by mass, and [2] an ink-jet printing method including the step of printing characters or images on a recording medium using the aforementioned water-based ink. The water-based ink of the present invention is excellent in long-term storage stability as well as ejection stability upon ink-jet printing, and can be improved in image quality of printed characters or images, rub fastness, water resistance, solvent resistance and adhesion to a substrate with a high level and a good balance when printed on a non-water absorbing recording medium.