The present invention refers to a process for the preparation of supported catalysts for the polymerization of olefins comprising at least a late transition metal complex, wherein the process comprises two steps. In the first step a catalytically active component comprising at least one late transition metal complex, optionally in the presence of one or more cocatalysts is mixed with a support; and in the second step the obtained mixture is treated at a reduced pressure under a flow of inert gas at a temperature equal to or below 40° C. to obtain a supported catalyst. The method is especially useful for the preparation of dual supported catalysts, useful in the gas-phase polymerization of olefins.