Polyvinylidene fluoride (PVDF)/multiwalled carbon nanotubes (MWCNTs) nanocomposites were prepared by solution blending method, and the melt viscoelastic behavior of the composites was studied. The results showed that the dispersion of MWCNTs in the matrix and the surface characteristic of MWCNTs had a profound influence on the melt rheological behaviors of the nanocomposites. Generally, the dynamic storage modulus (G') of the nanocomposites with well dispersed MWCNTs was greatly improved. However, PVDF/MWCNTs-g-OH nanocomposites exhibit more significant solid-like behavior than PVDF/MWCNTs nanocomposites at an MWCNTs loading of 2 wt % or higher, even though the dispersion of MWCNTs-g-OH is poorer than that of virgin MWCNTs owing to the higher interfacial interactions from van der Waals force and hydrogen bonding. In this case, the influence of the interfacial interactions on the melt rheological properties was stronger than the dispersion state. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121:3041-3046, 2011