The change in refractive index with temperature has been determined at atmospheric pressure for water, methanol, ethanol, 1-propanol, 1-butanol, n-amyl alcohol, pentane, hexane, heptane, octane, nonane, decane and four different kinds of dimethyl silicone oil from about 2 to 80°C. All measurements were made using the D spectrum of the natrium line (wavelength : 589.3 nm). Liquid sample was boxed in a small Pyrex container in order to prevent evaporation of test liquid during measurement. The Pyrex container was set into an Abbe refractometer. The measured refractive index for the length of 589.3 nm was transferred to that to the wavelength of 632.8 nm using dispersive power. The data of refractive index vs. temperature were fitted to a second-degree poloynomial. By differentiating tese equations with temperature, thermooptic coefficients dn/dT were obtained over the range of temperature. Estimated maximum error in the thermooptic coefficient is within 3%.