In the present work we studied the role of thermodynamic and kinetic parameters on determining multi-walled carbon nanotubes (MWCNT) localization in polycarbonate/styrene acrylonitrile (PC/SAN) blend nanocomposites. For this purpose, blend nanocomposites containing different amounts of PC, SAN and MWCNT were prepared by different orders of mixing. All the samples were prepared by melt compounding process in an internal mixer at temperature of 250 °C. The obtained SEM micrographs displayed a matrix-disperse morphology for the samples with a blend ratio of 20/80 and 80/20 of PC/SAN and co-continuous morphology for 60/40 PC/SAN. The MWCNT localization was examined by means of a combination of rheology and thermal analysis (DMTA). The melt linear viscoelastic results indicated that MWCNT had a better state of dispersion in PC/MWCNT sample compare to that in SAN/MWCNT which was found to be in consistent with thermodynamic calculations predicting a preferential localization of MWCNT in PC phase. This was evidenced by the melt viscoelastic and DMTA results that the MWCNT localization is independent of sequence of mixing but the blend’s components ratio had significant effect on MWCNT localization. These results suggested thermodynamic parameters are much stronger than kinetic parameters. These results were supported by the TEM micrographs obtained for the samples. Keywords: Rheology, Thermal Analysis, Morphology, Nanocomposite.