Аннотация:The structure of quantum corrections in supersymmetric theories regularized by higher covariant derivatives is investigated. We present the result of calculation of a two-loop β-function for the most general renormalizable N = 1 supersymmetric theory. All integrals, needed for obtaining this function, are integrals of total derivatives and can be easily calculated. For N = 1 supersymmetric electrodynamics we prove that contributions of planar diagrams with a single matter loop to the β-function are given by integrals of a total derivative in all orders.