Abstract Composites of Kraton-D® 1102 BT (a styrene–butadiene–styrene block copolymer) and multi-walled carbon nanotubes (MWCNTs) were prepared by melt mixing. The composites were characterized by electrical conductivity measurements (Coleman’s method), mechanical properties (DMA and stress–strain tests), thermal stability (thermogravimetry) and morphology of dispersion (SEM). Finally, the resulting composites were compared with those made by the solution casting method. The results showed a strong influence of the preparation methodology on the final properties of the composites due to changes in morphology. Composites prepared by casting showed a higher electrical conductivity than extruded ones; the composites with 6wt.% of MWCNT prepared by extrusion presented conductivity of the same order of magnitude as the composite with 1wt.% of MWCNT prepared by casting – 10−3 to 10−4Scm−1. However, the extruded samples presented better mechanical properties than the casting ones.