A process for preparing styrene by contacting a gaseous feed which contains 1-phenylethanol and at least 0.1% wt of phenol and/or ethylphenol with a heterogeneous dehydration catalyst in the presence of at least 0.40% wt of benzylalcohol and at a molar ratio of benzylalcohol to total amount of phenol and ethylphenol of at least 0.8.