An aqueous dispersion of polymer particles of a water-insoluble vinyl polymer containing a hydrophobic dye, wherein the water-insoluble vinyl polymer is prepared by polymerizing a monomer composition comprising an alicyclic (meth)acrylate, a salt-forming group-containing monomer, and a monomer copolymerizable with the alicyclic (meth)acrylate and the salt-forming group-containing monomer; and an ink comprising the aqueous dispersion. The aqueous dispersion is excellent in, for instance, storage stability, and the ink is excellent in, for instance, printing reliability, solvent resistance, water resistance and character quality.