Abstract Despite being a fundamental transport property, thermal diffusion in polymer solutions is still poorly understood, and reliable experimental data are scarce. After a brief review of previous experimental techniques and results, the application of forced Rayleigh scattering to the study of diffusion and thermal diffusion in polymer solutions is discussed. Due to the μm diffusion lengths, equilibration times are reduced to typically 100 ms, and signal averaging allows noise reduction. From a single experiment three different diffusion coefficients are obtained without the need for chain labeling: the thermal diffusivity, the translational diffusion coefficient, and the thermal diffusion coefficient. An improved setup, allowing convection-free heterodyne detection, is discussed. Results for polystyrene in toluene and ethyl acetate are reported, and the measured translational diffusion coefficients are compared with data obtained from photon correlation spectroscopy.