The impact of surface finish on rotary beam fatigue life of 0.323 mm Nitinol (Ni 56wt%-Ti) wire are studied.  In preparation of the wire samples, processing parameters such as cold work reduction and annealing were held constant for all surface conditions investigated. Various Niti wire surfaces such as black oxide, pickled, light oxide, etched, mechanically polished and electro-polished surfaces are evaluated.   These wires were subjected to alternating compression-tension cycles at strain levels ranging from 0.5% to 2.5% at body temperature.  The choice of surface preparation has a decided effect on the ultimate rotary beam fatigue life and becomes an important engineering design consideration necessary for the optimization of wire based implant medical devices.