The syntactic foams based on polymethylphenylsiloxane resin filled by hollow glass microspheres were developed for using in different applications of construction industry. Thermophysical properties of the developed syntactic foams were analyzed in this work. According to the study results, with an increase of polymethylphenylsiloxane content in the syntactic foam, the thermal conductivity and the specific heat capacity increased. The coefficient of thermal linear expansion was dependent on the ratio of the components, reaching the lowest value for the composites with a minimum binder content.