A water-based ink comprising an aqueous dispersion of polymer particles made of a water-insoluble vinyl polymer containing a colorant, wherein the water-insoluble vinyl polymer is prepared by polymerizing a monomer composition comprising a specific monomer A such as a monomer A1 represented by the formula (I): ##STR00001## wherein R.sup.1 is hydrogen or methyl, R.sup.2 is hydrogen, alkyl or alkylphenyl, and n is 1 to 30; a monomer having a salt-forming group; and a monomer copolymerizable with the monomer A and the monomer having a salt-forming group. The water-based ink can be suitably used as a water-based ink for inkjet recording and the like.