The invention is related to a cost-effective method for making a silicone hydrogel contact lens having a crosslinked hydrophilic coating thereon. A method of the invention involves autoclaving, in a sealed lens package, a silicone hydrogel contact lens having a base coating of polyacrylic acid thereon in an aqueous solution in the presence of a water-soluble, crosslinkable hydrophilic polymeric material having epoxide groups, for a period of time sufficient to covalently attach the crosslinkable hydrophilic polymeric material onto the surface of the silicone hydrogel contact lens through covalent linkages each formed between one epoxide group and one of the carboxyl groups on and/or near the surface of the silicone hydrogel contact lens.