Abstract We report the synthesis of high-quality Co-doped ZnO thin films using the pulsed laser deposition technique on (0 0 0 1)-Al 2O 3 substrates under an oxidizing atmosphere, using Zn and Co metallic targets. The growth of ZnO was optimized in order to obtain the least strained film using the sin 2 Ψ model. Highly crystallized Co:ZnO thin films are obtained by an deposition from alternating Zn and Co metal targets. This procedure results in homogenous incorporation of the Co in the ZnO wurtzite structure, which is confirmed by the linear dependence of the out-of-plane lattice parameter as a function of the Co dopant up to 9%. The Zn 1− x Co x O films exhibit ferromagnetism with a Curie temperature close to room temperature for x=0.08 and at 150 K for x=0.05.