Variable angle spectroscopic ellipsometry measurements (see Figure for principle) show that thin spin-cast films of MEH-PPV are highly anisotropic. Accurate dispersion data for the refractive index and the dielectric function of MEH-PPV in the energy range 1.24 to 5.00 eV are also given. [GRAPHICS] Measurement of the Anisotropic Refractive Indices of Spin Cast Thin Poly(2-methoxy-5-(2'-ethyl-hexyloxy)-p-phenylenevinylene) (MEH-PPV) Films.