We calculate the anisotropic elastic coefficient of composites of oriented ellipsoids in the effective medium approximation. The theoretical prediction is compared with experimental results for the longitudinal and transverse Young’s modulus of injection molded polymer blends of an amorphous thermoplastic polyester and an ethylene‐propylene‐diene rubber at different compositions. The different ‘‘percolation limits’’ experimentally observed are reproduced. ©1995 American Institute of Physics.