The electrooptical properties of carbosilane dendrimers with different structures of terminal polar groups were studied in toluene and chloroform. The Kerr constants of all dendrimers were found to be independent of the generation number and correspond by order of magnitude to the Kerr constants of compounds modeling their terminal mesogenic fragments. The Kerr constants of the dendrimers calculated according to the principle of the additivity of the electrooptical constants of the core and mesogenic groups taken with their weight factors were shown to coincide with the measured Kerr constants. The electrooptical properties of dendrimers with mesogenic terminal groups were found to be determined by the parameters of the electric structure and the optical characteristics of the polar terminal groups, whose orientations in an electric field were virtually independent of each other.