Amorphous diamondlike carbon films have been investigated by means of spectroscopic ellipsometery (SE). The films were measured by a null ellipsometer in the 230-750 nm range and the measured spectra were analyzed using an empirical dielectric function suitable for amorphous materials. The fitting of SE data with empirical dielectric function shows that the measured spectra can be well explained using the empirical dielectric function. The optical constants calculated from the fitting of SE data were used to calculate the optical reflectance spectra of these films. It was found that the calculated reflectance spectra coincide with the measured spectra suggesting that the optical properties obtained from the fitting of SE data are accurate.