A process for the preparation of a solid olefin polymerization catalyst or a solid olefin polymerization catalyst component comprising the steps of: (a) forming a liquid/liquid emulsion of (i) a first organic liquid comprising at least one olefin polymerization catalyst component and (ii) an optionally halogenated hydrocarbon liquid immiscible therewith; where the first organic liquid forms the dispersed phase and the optionally halogenated hydrocarbon liquid forms the continuous phase of the liquid/liquid emulsion and wherein the dispersed phase forms droplets in the continuous phase; and (b) transforming the droplets of the dispersed phase to solid particulate particles comprising said at least one olefin polymerization catalyst component, wherein the liquid/liquid emulsion is stabilized with a solid particulate stabilizer.