A novel method for the preparation of supported metallocene/alkylaluminoxane catalysts has been developed. An incipient wetness impregnation of silica at ca. -40 degreesC is performed in one step employing a solution of catalyst and cocatalyst in 1-hexene. A prepolymerization of this system at ambient temperature yields a catalyst robust towards exposure to air, as demonstrated by a reasonable activity during ethene polymerization. A special feature of the catalyst is a uniform impregnation across the silica particles.