We present preparation and magnetic properties of quaternary diluted magnetic semiconductor (InyGa1-y)(1-x)MnxAs epitaxial layers grown by molecular beam epitaxy (MBE). (In0.53Ga0.47)(1-x)MnxAs grown on InP substrates shows ferromagnetic order up to 60 K. Curie temperature shows linear dependence on effective Mn composition x(eff), and can be expressed in the form: T-C = 1300x(eff). (C) 2002 Elsevier Science B.V. All rights reserved.