The application of resonance acoustic spectroscopy (RAS) for the purpose of nondestructive evaluation (NDE) of various properties of a clad rod is investigated in this paper. RAS is the study of the resonances of an elastic object, which are excited by an incident wave, for characterization of the material properties of the elastic object. The equations for the backscattered pressure field from an elastic/viscoelastic clad rod at both normal and oblique incident angles are derived. Numerical studies show how RAS can effectively help in monitoring the variations of the cladding thickness and cladding delamination. Experimental measurements, conducted on copper-clad aluminum rods, are found to be consistent with numerical results obtained from the mathematical model. It is demonstrated that there exists a potential for using RAS for NDE and on-line monitoring of various properties of clad rods.