Optical Kerr effect investigations in liquid and gaseous carbon dioxide and the temperature dependence of this effect are reported. From our studies information concerning the molecular interactions and local structure of the medium were obtained. Using the method of indirect comparrison of the results of optical Kerr effect for liquids and gases it is found that the contribution to optical birefringence from a single CO2 molecule in gas and vapor phase is about 7 and 3. 5 times greater respectively than the contribution of the same molecule when in liquid phase. It is also shown that. the effective molecular anisotropy of the carbon dioxide molecule in the liquid phase is markedly lower than its value in the gas phase. This fact is interpreted as an effect of molecular interactions among CO2 molecules which are much stronger in the dense medium.