This invention relates to inks for use in ink-jet printers that are cured using ultraviolet radiation. Specifically, the present invention relates to an ink-jet ink which is substantially free of water, volatile organic solvents and multifunctional (meth)acrylates comprising at least one monofunctional (meth)acrylate monomer, at least one α,β-unsaturated ether monomer, at least one radical photoinitiator and at least one coloring agent, the ink having a viscosity of less than 50 mPas at 25° C. This provides extra-low viscosity inks, which still meet the requirements for printing onto porous substrates such as paper and board.