An airfoil design technique is described which uses an analytical method for representing the airfoil contour by Wagner functions and a computational procedure for obtaining the values of the coefficients of expansion. The method for approximating an airfoil contour by a Fourier-type series of Wagner functions is briefly outlined, and a flow chart for airfoil design by optimization is given. The design technique is validated by applying it to the NACA 0009 airfoil as well as to a typical airfoil that gives a 'roof-top' pressure distribution. Advantages of this technique over classical design methods are discussed.