The nature of the electrical resistivity for low doped lanthanum manganites is elucidated. The electrical resistivity is described by the Efros-Shklovskii law (lnρ ∝ (T 0 /T) -1/2 , where T 0 ∝ 1/R ls ) in the tem perature range from T* ≈ 300 K ≈ T C (T C is the Curie temperature for conducting manganites) to their T C and is explained by the tunneling of carriers between localized states. The magnetoresistance is explained by a change in the size of localized states R ls in a magnetic field. The patterns of change in R ls with temperature and magnetic field strength determined from magnetotransport properties are satisfactorily described in the model of phase separation into small radius metallic droplets in a paramagnetic matrix. The sizes R ls and their temperature dependence have been estimated through magnetic measurements. The results confirm the existence of a Griffith phase. The intrinsic inhomogeneities produced by thermodynamic phase separation determine the electrical resistivity and magnetoresistance of lanthanum manganites.