The effects of the &rgr; − &ohgr; mixing term in infinite nuclear matter and in finite nuclei are investigated with the non‐linear Walecka model in a Thomas‐Fermi approximation. For infinite nuclear matter the influence of the mixing term in the binding energy calculated with the NL3 and TM1 parametrizations can be neglected. Its influence on the symmetry energy is only felt for the TM1 with a unrealistically large value for the mixing term strength. For finite nuclei the contribution of the isospin mixing term is very large as compared with the expected value to solve the Nolen‐Schiffer anomaly. © 2003 American Institute of Physics