Exchange bias (EB) has been observed for all-manganite La0:7Sr0:3MnO3=SrMnO3=La0:7Sr0:3MnO3 trilayers with ferromagnetic La0:7Sr0:3MnO3 and G-type antiferromagnetic SrMnO3 (SMO) layers, grown on (001) SrTiO3 substrates by metalorganic aerosol deposition. The field shift of the magnetic hysteresis loop He and the coercivity Hc decay exponentially with temperature. HE exhibits a global maximum as a function of SMO interlayer thickness at t(SMO)~4.5 nm. We argue that EB behaviour can be explained by the interplay of a spinglass state at the interface and theoretically proposed mechanism based on the Dzyaloshinskii-Moriya interaction.