The hopping conductivity ofLa2CuO4+&dgr;single crystal with excess oxygen has been studied. It is found that the transition from variable-range hopping (with the temperature dependence of resistanceR∝exp(T0/T)1/4) to simple activation conductivity(R∝exp(&Dgr;/kT))occurs at a temperature lower than20 K.This transition is accompanied with significant changes in the behavior of magnetoresistance and current–voltage characteristics. It is shown that such a behavior of hopping conductivity below20 Kis due to the presence of superconducting inclusions in insulating sample due to phase separation ofLa2CuO4+&dgr;.The observed peculiarities in the conducting properties are in good agreement with the known effects of competition between electron localization and superconductivity in homogeneous systems. ©1997 American Institute of Physics.