To understand the effect of Co doping on the magnetic entropy changes in Gd2 Al phase, a series of Gd2AlCox alloys with 0 ≤ x ≤ 0.6 were synthesized by arc-melting and the crystal structure was analyzed by XRD. The magnetic properties were investigated, and the entropychanges were calculated for a magnetic field change of 50 kOe. All the as-cast alloys dopedwith Co exhibited greater magnetic entropy changes than the original binary Gd2 Al phase. The main reasons attributed to this are the increase of ferromagnetic interaction indicated by the disappearance of cusp and sharp drop in magnetization and the reduction of the critical field required to trigger the field-induced transition below 50 K in Gd2 Al phase after Co alloying.