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Resistive properties of point contacts in normal-metal-manganite heterojunctions have been investigated on the base of La0.7Sr0.3MnO3, La0.8Sr0.2MnO3, La0.8Ca0.2MnO3 single crystals. At considerable current levels the current-voltage characteristics of point contacts exhibit features in the form of resistance peaks at lower temperatures. Colossal magnetoresistance also considerably increases under transport current in the investigated heterojunctions. It has been assumed that the observed current switching effects are due to phase separation of manganites under the electric current.Introduction. -It appears that phase separation is one of the key problems both with high-temperature superconductors (HTSC) and doped manganites, i.e. the systems possessing different "working" properties (superconductive state in HTSC and colossal magnetoresistance (CMR) in manganites). Manganites fall into the category of strongly correlated electronic systems, the ferromagnetic state results from the so-called double exchange (see refs. [1][2][3]). But spatially homogeneous phases turn out to be less energetically favourable than inhomogeneous ones. Recent results suggest that in doped manganites paramagnetic (or antiferromagnetic) and ferromagnetic phases can coexist in the phase separation (PS) state in a broad temperature range below the Curie point [4][5][6][7][8]. The theoretical works predict that the PS state is a fine-dispersed state arising from a competition between the Coulomb and magnetic interaction at a specific degree of doping either with rare-earth element or oxygen. Today there are two approaches to the PS problem, namely, PS is a result of the electronic phase transition or, else, phase separation is caused by structural or composition inhomogeneity. The PS state is assumed to arise in the systems with a strong electron-phonon interaction and in polaron systems. The PS state can be stimulated by external actions, i.e. by magnetic and electric fields, irradiation of photons.In order to study PS states in manganites, we examined point contacts in normal-metalmanganite heterojunctions. An electric field is distributed nonuniformly in point contacts, the electric field intensity being quite large at the electrode boundary.