Filled epoxy composites are broadly used in electronic and power devices as an electrical insulation. It is of importance to achieve an efficient heat dissipation in such devices due to fact that thermal properties have a strong influence on their proper operation. For this reason, the modification of standard filler materials, such as silica or alumina, can give a promising solution. In this paper, a several methods for thermal conductivity enhancement will be discussed and experimental results will be shown, namely: a) incorporation of the hybrid fillers [1], b) use of magnetic field-assisted filler alignment technology [2], c) synthesis and application of a novel core-shell materials [3]. The composite samples based on epoxy resin filled with the modified fillers have been investigated in order to determine the effective thermal conductivity. The obtained composite samples exhibited a significant improvement in the thermal conductivity. The results were analyzed with use of various theoretical models. Additionally the mechanical and dielectric measurements were performed showing a high potential for the composites with incorporated new modified fillers to be applied for the electrical insulation with the enhanced thermal conductivity. References: 1. K. Gaska, A. Rybak, C. Kapusta et al., Polym. Adv. Technol. 2015, 26, 26. 2. K. Gaska, G. Kmita, A. Rybak, et al., J. Mater. Sci. 2015, 50, 2510. 3. A. Rybak, K. Gaska, J. Mater. Sci. 2015, 50, 7779.