An electrophotographic printing toner including a colorant and a resin, wherein the colorant includes a dye having at least one reactive group selected from the group consisting of SO.sub.2C.sub.nH.sub.2nOSO.sub.3H, NHCOC.sub.nH.sub.2nOSO.sub.3H, NHSO.sub.2C.sub.nH.sub.2nOSO.sub.3H, COC.sub.nH.sub.2nOSO.sub.3H and SO.sub.2CHCH.sub.2, wherein n represents an integer of from 1 to 4.