Abstract: Disclosed is an ink composition which has superior storage stability, is resistant to bleeding, has good fixability to paper, and enables printing of a clear image. The ink composition includes a pigment dispersion containing a surface-treated pigment and a resin emulsion, wherein the surface-treated pigment is obtained by binding a functional group, having a larger calcium index than a calcium index of 1,2,3-benzenetricarboxylic acid, to the surface of a pigment; and the resin emulsion is adapted so that an aqueous solution containing 1 mass % of a solid content of the resin emulsion has a conductance of 300 ?S/cm or less.