Described herein is a cost-effective and time-efficient method for making UV-absorbing contact lenses. In contrast to the conventional method for making UV-absorbing contact lenses which involves copolymerizing a lens forming composition including a UV-absorbing vinylic monomer, a method of the invention involves covalent attachment of a UV-absorbing compound having a second reactive functional group to a preformed contact lens having a first reactive functional group therein and/or thereon.