Abstract: A process for covalently attaching an antimicrobial coating to a polymeric surface. The process comprises contacting the surface of the polymer with a plasma having reactive nitrogen compounds to provide a plasma-treated surface with —NHR groups, wherein R is hydrogen, hydroxyl or C1-2alkyl, reacting the —NHR groups with a surface linking agent, and attaching an amine-containing polymer to the linking agent to form the antimicrobial coating. The surface linking agent is selected from the group consisting of dihaloalkyl, a dihaloalkenyl, and a dihalomethylaryl. The invention is also directed to a contact lens case or a contact lens with an antimicrobial coating.