Inkjet ink compositions comprising a liquid vehicle and a modified azo pigment are described. The modified azo pigment comprises the reaction product of at least one diazonium reagent and at least one azo coupler. At least one of the diazonium reagents and/or azo couplers may comprise at least one ionic group, ionizable group, or mixture thereof or at least one alkylene oxide group. The inkjet ink composition does not include a separate dispersant which primarily functions to obtain or maintain stability of the modified azo pigment or the ink jet ink composition. Methods of preparing the inkjet ink compositions are also described.