For the prediction of thermophysical properties of transparent liquids by means of light scattering, the refractive indices and densities are indispensable quantities. The temperature dependence of the refractive index at two laser line wavelengths (Ar-ion, 514 nm, and He-Ne, 632.8 nm), and the density of carbon tetrachloride, chloroform, and dichloromethane are presented at temperatures from T = 290 K to T = 340 K at atmospheric pressure. An unusual linear temperature dependence was observed for both quantities, which is in harmony with the empirical correlation equation of Ward and Kurtz. On the basis of our results and literature data it can be concluded that the linear temperature dependence of refractive indices and densities is only valid for aprotic solvents. A description of the practical application of the Abbe refractometer at the laser lines is also given.