An ink composition capable of offering a combination of a high-quality image with a waterfast image is provided. More specifically, an ink composition is provided which, by virtue of a combination of particular dyes, can faithfully reproduce black color, realize a high-quality image (a sharp image having a high optical density and free from bleed) also on plain paper and, at the same time, offer rapid ink fixation and waterfastness and lightfastness of the printed image. Dyes represented by the following formula (I) are used as a fundamental dye and further combined with a plurality of dyes to constitute the ink composition: ##STR1## wherein R.sup.1 represents --PO(OM).sub.2 or --COOM, X and Y each independently represent an alkoxy and M represents a cation of a group selected from the group consisting of a hydrogen atom, an alkali metal, ammonia, and an organic amine.