Results of comparative liberation tests on electrically disintegrated and mechanically comminuted oxide ores containing hematite and PGM and sulphide ores containing complex Cu sulphides and pentlandite showed that disintegration of ore aggregates by electrical pulses generates a higher percentage of liberated particles and lower percentage of fine material than that obtained by mechanical comminution. Mechanism of electrical disintegration creating a specific liberation process by splitting mineral aggregates along boundaries of minerals with different electrical parameters is described. The main effect of liberation by electrical pulses manifests in the generation of a higher percentage of the coarse monomineral particles and in the general increase of liberated material with dimensions of particles, which can be efficiently treated by the separating equipment. Comparative amount of monomineral particles in the fine (< 106 m) fractions of the sulphide ores fragmented by both methods does not differ substantially, while in the coarser particles (>106 mum), this difference sometimes exceeds 40%. General improvement in the recovery and grade was achieved on both oxide ores and in the pentlandite ore.