In this study, we investigated the effect of an aromatic polymer, styrene ethylene butadiene styrene (SEBS), on the water-tree resistance of crosslinked polyethylene (XLPE), and the synergetic effect of SEBS and ethylene vinyl acetate (EVA) was also investigated. The XLPE/SEBS and XLPE/SEBS/EVA samples were characterized by means of differential scanning calorimetry, scanning electron microscopy, mechanical measurements, and an accelerated water-treeing experiment, and the obtained results clearly show the relevant influence of SEBS and EVA, and as expected, the addition of SEBS and EVA was found to synergistically influence the water-tree resistance of XLPE more positively in comparison with that without the addition of EVA. In addition, it also indicated that the blends possessed excellent dielectric behaviors, such as the dielectric constant and dissipation factor. The crystallization of the blends decreased with increasing SEBS content and addition of EVA. However, the melting temperature of the blends increased with the addition of SEBS and EVA, but the melting temperature of the blends decreased with increasing SEBS content. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 2350-2357, 2010