Optical and compositional properties of In, In/Pd and Pd/In/Pd thin films evaporated on Cu and SiO₂ substrates in vacuum were investigated by means of X-ray diffractometry, Auger electron spectroscopy and spectroscopic ellipsometry methods. Auger depth profile studies were performed in order to determine the composition of InCu and InPd structures. In both systems interdiffusion of metals was detected at room temperature. The XRD patterns indicated formation of CuIn₂ and PdIn₃ phases in the samples. Optical properties of the composite layers containing intermetallic phases were derived from ellipsometric quantities Ψ and Δ measured in the photon energy range 0.1-6.0 eV at different angles of incidence using suitable multilayer models for the examined samples.