Thermal conductivity and heat capacity of composites of ABS resin with glass beads and/or titania were measured. For ABS-glass-beads composites, the thermal conductivity data are in good agreement with values calculated by the Maxwell and Bruggeman equations in a temperature range above a critical temperature, but much deviation was observed below this temperature. Similarly for the heat capacity, the measured data are in excellent agreement with the calculated values assuming additivity above the critical temperature, while the measured data are clearly less than the calculated values below this temperature. On the other hand, for the ABS-titania the measured data of heat capacity are higher than the additivity in the whole temperature range, though linearity was found among titania and the composites also in the whole temperature range. The thermal conductivity observed for this composite is in good agreement with the theoretical value calculated by the Maxwell and Bruggeman equations except in a low temperature range. By dynamic viscoelastic observation, it was found that a new dissipation occurs around 95ΠC in the composite of the glass beads. These facts suggest that interaction exists between the resin and the fillers, and this interaction causes the deviation from the Maxwell and Bruggeman equations in the thermal conductivity and deviation from the additivity in the heat capacity below the critical temperature. For the composite of titania no new dissipation was found, but a small dissipation originally observed for the resin was not seen.