The present invention provides a polymeric optical waveguide film whose core and clad are constituted from polymer materials and which is characterized in that a protective layer of a polymer material having resistance to solvent attack higher than that observed for the clad is arranged on at least one of the surface and back face of the waveguide film. The present invention thus permits the preparation of such a film, the clad of which is hardly damaged, which is excellent in the resistance to solvent attack and which never undergoes cracking even when it is bought into contact with a commonly used solvent such as acetone.