A lattice-mismatched ZnTe epilayer on a GaAs (100) substrate was grown by the simple method of temperature-gradient vapor deposition. From the x-ray diffraction analysis, the grown layers were found to be ZnTe epitaxial films. The stoichiometry of the ZnTe films was investigated by Auger electron spectroscopy. Transmission electron microscopy measurements showed that there was a large lattice mismatch between the ZnTe epitaxial layer and the GaAs substrate. These results indicate that ZnTe epitaxial films grown on GaAs substrates at 320-degrees-C have no significant interdiffusion problems, and that pseudomorphic, fully strained ZnTe layers are observed for deposits after ten molecular layers.