This invention relates to a printing ink and in particular to an ink for ink-jet printing which is cured by irradiation. The ink comprises at least one radiation-curable monomer; at least one passive thermoplastic resin; at least one radical photoinitiator; and at least one colouring agent; wherein the ink has a viscosity of less than 100 mPas at 25° C., and wherein the at least one passive resin is present at 2 to 15 wt % based on the total weight of the ink and has a molecular weight of 1,500 to 70,000.