The purpose of this study is to identify factors that affect superelastic Nitinol fatigue resistance using a commercially available wire specimen. The study reveals the fatigue resistance of Nitinol wire as functions of surface finish, inclusions, processing, and applied stress applied. Nitinol wires were fatigue tested using the rotating beam fatigue method. The sample strains were verified using a direct strain-measurement method. Wires with outer diameters ranging from 0.127 to 0.343 mm processed with a mechanical and/or electropolished surface finish were compared to one another.