Abstract-A novel ortho-mode transducer (OMT) for dual-band dual-polarized communication systems is proposed in this letter. The OMT is loaded with five posts in reasonable positions of the waveguides and a shorted circuit piston in the branch waveguide. Compared with the septum loaded traditional one, the presented OMT is more flexible, simple and easy to fabricate. Both simulations and measurements indicate that the impedance bandwidths of VSWR<1.15 ranging from 6.50 to 7.20 GHz and 8.80 to 10.2 GHz can be obtained. The low insertion losses indicate that the presented OMT can be used in actual project. Moreover, good isolation performance between the two input ports in both bands are obtained because of the inherent existence of cross polarization.