This work examines the influence of annealing temperature on the transformation temperatures, stress necessary to induce martensite (sAM), and the Young's modulus of superelastic NiTi of two different compositions--47.5 at.% Ni and 50.5 at.% Ni. The films were sputter deposited, crystallized, and annealed for two hours at three different temperatures of 400°C, 500°C, and 600°C. Isothermal tensile tests at the austenite finish temperature (Af) were performed for evaluating the mechanical response. For the 47.5 at.% Ni film, increasing the annealing temperature from 400°C to 500°C decreased sAM by 55 MPa, while the film annealed at 600°C failed to demonstrate complete superelastic behavior. For the 50.5 at.% Ni film, increasing the annealing temperature from 400°C to 600°C decreased sAM by 138 MPa. Results were explained using the transformation temperatures and the Clausius-Clapeyron relationship.