ABSTRACT: Multi-walled carbon nanotubes (MWNTs)/Nylon-12 nanocomposites with different MWNTs (1-5wt.%) loadings have been prepared by the simple melt-compounding approach at 200 °C for 20 mins with a rotation of 150 rpm for all the composites. A dark and homogeneous Nylon-12/MWNTs nanocomposite was collected from extruder after 20 mins melt-compounding. A fine and homogeneous dispersion of MWNTs throughout Nylon-12 matrix is observed by transmission electron microscopy (TEM). Scanning electron microscopy (SEM) observation on the fracture surfaces of the composites shows not only a uniform dispersion of MWNTs but also a strong interfacial adhesion with the matrix, as evidenced by the presence of many broken but strongly embedded carbon nanotubes (CNTs) in the matrix and by the absence of de-bonding of CNTs from the matrix. Mechanical testing by tensile tests as well as dynamic mechanical analysis shows that, compared with neat Nylon-12, the storage modulus and the tensile strength of the nanocomposite are greatly improved by about 113% and 134%, respectively, with incorporating only 3 wt % MWNTs. In addition to the above mechanical analysis, crystallization and melting behavior of Nylon-12/MWNTs nanocomposites are also observed and discussed by differential scanning calorimetry and X-ray diffraction. Keywords: CNT; Melt processing; Mechanical properties; TEM; SEM.