This review aims to provide a summary of some of the challenges in correlating surface science and biology, with particular emphasis on areas where plasma polymerization has and will play an important role as a method to synthesize reproducible and well-defined surfaces. Since the range of possible applications of plasma polymer films in biomaterial applications is immense, this paper will focus on processes to develop various surface morphologies and chemical structures for the immobilization of proteins and cells. Functional, plasma-polymerized films are discussed as biosensitive interfaces that may ultimately be part of a multilayer system that aims at connecting inorganic/metallic transducers with biologically reactive surfaces. These topics will be reviewed with some experimental results taken from the authors' own work. Specific aspects such as adhesion improvement and solvent effects are also discussed.