[en] Shape optimization requires a proper geometric representation of the blade profile; the parameters of such a representation are usually taken as design variables in the optimization process. However, the designer is more familiar with the traditional design parameters; for turbine blades these would be the leading and trailing edge radii, wedge angles, blade angles, as well as the blades stagger angle, spacing, etc. This work is concerned with the representation of the blade profile in terms of NURBS functions that implicitly satisfy the traditional designer parameters and provide enough flexibility and accuracy to represent any turbine blade shape. This NURBS representation is then tested on two distinct turbine blade shapes to demonstrate the NURBS accuracy and flexibility in capturing a target blade profile or a target blade curvature distribution and area. (author)