We suggest a separation of variables method based on expansions of the electromagnetic fields in terms of spheroidal wave functions. Our approach includes splitting the fields in two specific parts and choice of proper scalar potentials for each of them. An earlier analysis of similar methods in the case of a spherical basis has shown that the SVM has a wider practical applicability range than other methods. It was also found that when using a spheroidal basis our general approach gave reliable results for particles of high eccentricity for which other approaches were inapplicable. Thus, the suggested SVM should be highly efficient in calculations of optical properties of various nonspherical scatterers in a wide range of parameter values.