This video describes the surface modification of medical devices to improve their biocompatibility. Two plasma-chemistry processes are detailed. Firstly, the activation of a surface that consists of polymethylpentene, a procedure that aims at increasing the biocompatibility of artificial lungs. Secondly, it is demonstrated how the surface of titanium can be coated. The ultimate goal of this surface functionalization is the minimization of the body’s intolerance to pacemakers.