Evidence of elastic tunneling has been observed in YBa2Cu3O7−δ(S)∕La1∕3Ca2∕3MnO3(AF)∕La2∕3Ca1∕3MnO3(F) junctions. S/AF/F trilayers with thicknesses of ∼100, ∼7, and ∼80nm, respectively, were grown on SrTiO3 (001) substrates. Electrical measurements of the junctions at low temperatures under zero magnetic field display an asymmetry of the I-V and G(V)≡dI∕dV characteristics: for positive voltages, we observed a sharp peak at ∼20meV at 15K; for negative voltages we find at this temperature a peak around −15meV in agreement with the value expected for YBa2Cu3O7−δ. The low values of the conductance G for voltages above the energy gap are discussed.