Expressions are derived for the distributions in size and composition of the macromolecular products of random degradation of diblock copolymers with arbitrary block length distributions. Equations for the calculation of the angular dependence of the static structure factor of these products formed at different depths of degradation are presented. General regularities of the evolution of the spinodal of the polymer melt in the course of this reaction are analyzed. Proceeding from the general theory developed, examples concerning degradation processes of diblock copolymers with particular block length distributions are provided.