The present invention refers to a method of making a ready-to-use catheter assembly, a catheter assembly for use in the method, a ready-to-use catheter assembly and a wetting medium for use in the method. It is an object of the present invention to provide a ready-to-use catheter assembly which can be immediately used by a patient without the necessity for any preparation steps and a method of making such a ready-to-use catheter assembly which ensures that the catheter does not suffer from a loss of quality during its shelf life. Therefore, the method comprises the following steps:Placing a catheter with an inactivated hydrophilic outer surface at least along its insertable length and a wetting medium in a catheter package. Treating the catheter package with the catheter and the wetting medium with electro-magnetic and/or particle radiation while at least initially the hydrophilic outer surface at least along the insertable length of the catheter remains inactivated. Activating the hydrophilic outer surface at least along the insertable length of the catheter with the wetting medium during and/or after the radiation treatment and wherein the wetting mediumdecreases in viscosity when submitted to electro-magnetic and/or particle radiation. A ready-to-use catheter assembly comprises a catheter package, a catheter with a hydrophilic outer surface at least along its insertable length arranged in the catheter package and a wetting medium which is also arranged in the catheter package and which is in contact with the hydrophilic outer surface at least along the insertable length of the catheter so that the hydrophilic outer surface is activated and wherein the wetting medium is a gel comprising at least one solute polymer and has a viscosity below 1000cP, preferably 100cP.
