The leakage current in all oxide epitaxial (La,Sr)MnO3-ferroelectric-(La,Sr)MnO3 structures, where the ferroelectric layer is either BaTiO3 or Pb(Zr0.2Ti0.8)O3, was analyzed on a broad range of temperatures and for different thicknesses of the ferroelectric layer. It was found that, although the structures are nominally symmetric, the current-voltage (I–V) characteristics are asymmetric. The leakage current depends strongly on the thicknesses of the ferroelectric layer, on temperature and on the polarity of the applied voltage. Simple conduction mechanisms such as space charge limited currents or thermionic emission cannot explain in the same time the voltage, temperature, and thickness dependence of the experimentally measured leakage currents. A combination between interface limited charge injection and bulk controlled drift-diffusion (through hopping in the case of BTO and through band mobility in the case of PZT) is qualitatively explaining the experimental I–V characteristics.