An antimicrobial medical device that includes a substrate having a metal surface that is made from a metal or metal alloy that may include stainless steel, cobalt, and titanium. Disposed on the metal surface is a first antimicrobial oxide layer that includes an antimicrobial metal that may include silver, copper, and zinc, and combinations thereof. The atoms of antimicrobial metal in the first antimicrobial oxide layer are of a first concentration. The first antimicrobial oxide layer is positioned in a direction opposite that of the metal surface. The device further includes a second antimicrobial oxide layer that includes an antimicrobial metal that may be silver, copper, and zinc, and combinations thereof. The atoms of the antimicrobial metal present in the second antimicrobial oxide layer are of a second concentration. The first concentration and the second concentration are not equal. Methods for making the antimicrobial medical device are also disclosed.