Polynorbornene is a class of polymer that exhibits significant potential as a structural material in microelectromechanical systems owing to its dielectric constant and compatibility with silicon-based microfabrication processes. A commercially available version of PNB (AvatrelTM 2585P) is particularly attractive for bioMEMS applications because of its low moisture absorption characteristics, photodefinability, and potential biocompatibility. This study furthers the advancement of PNB as an enabling structural material for microfluidics and flexible bioMEMS applications by developing the following key processing techniques: (1) oxygen plasma-based surface modification for bonding PNB layers to glass substrates, and (2) the monolithic fabrication of free-standing, mechanically flexible electrode arrays using silicon wafers as mechanical supports during fabrication. To further develop PNB for flexible, implantable bioMEMS applications, this study also includes an evaluation of: (1) the tensile properties of free standing structures after accelerated lifetime testing in phosphate-buffered saline, and (2) the in vitro performance of free-standing, mechanically flexible neural microelectrode array-based neural interfaces. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40969.