In this communication, multiwalled carbon nanotubes (MWNTs)/nylon 6 (PA6) nanocomposites have been prepared by simple melt-compounding. Scanning electron microscopy (SEM) observation on the fracture surfaces of MWNTs/PA6 sample indicates that a homogeneous dispersion of carbon nanotubes (CNTs) throughout PA6 matrix has been successfully achieved. Mechanical tests show that, compared with neat PA6, the tensile modulus, the tensile strength and the hardness of the composite are greatly improved by about 115%, 120% and 67%, respectively, with incorporating only 1 wt% MWNTs. Close inspection by SEM shows a strong interfacial adhesion between CNTs and PA6 matrix, which is responsible for the significant enhancements in mechanical properties.