The present invention relates to [1] a pigment-containing water-based ink for ink-jet printing which is free of turbidity and excellent in capability of suppressing occurrence of image unevenness (MOTTLING) when printed on a low-water absorbing recording medium, said ink including at least one acetylene glycol (A) selected from the group consisting of 2,4,7,9-tetramethyl-5-decyne-4,7-diol and the like, and a nonionic surfactant (B), a content of the component (A) in the water-based ink being not less than 1.0% by mass and not more than 3.0% by mass, and a mass ratio of the component (B) to the component (A) [(B)/(A)] being not less than 1 and not more than 3; and [2] an ink-jet printing method for printing images or characters on a low-water absorbing recording medium using said water-based ink for ink-jet printing.