This paper presents a new technique for the determination of the dispersion diagrams of dielectric waveguides embedded in a stratified media. The method consists of a boundary formulation of the problem in terms of an integral equation on the waveguide surface. Numerical results are obtained by applying the moment method. As an example of application, the case of a guiding core of arbitrary cross section embedded in a homogeneous half-space has been considered. The computer program requires small computer memory and time; in test cases the results agree with those obtained with other methods.