New thermoplastic elastomeric blends based on hydrogenated styrene-butadiene rubber (HSBR) and low-density polyethylene (LDPE) were prepared by the melt blending technique. The rheology, structural and mechanical properties were measured as a function of blend composition. The HSBR/LDPE blend had a higher tensile strength, modulus, and work-to-break with low elongation at break compared with those of pure HSBR. X-ray diffraction studies demonstrated co-crystallisation and a remarkable increase in the degree of crystallinity. The improvement in the mechanical properties and the uniform morphology were correlated with the interfacial adhesion and compatibilisation of the HSBR/LDPE blend through ethylene segments. The experimental results for the HSBR/LDPE blends were compared with those for HSBR/high-density polyethylene (HDPE) and SBR/LDPE blends. The mechanical properties of the HSBR/LDPE blend were found to be superior. The results were explained on the basis of morphology and interaction.