The miscibility of C-60-containing poly(methyl methacrylate) (PMMA-C-60) with poly(vinylidene fluoride) (PVDF) was studied. Two PMMA-C-60 samples containing 2.6 and 7.4 wt % C-60 were found to be miscible with PVDF based on single glass transition temperature criterion and melting point depression of PVDF. However, the interaction parameters of the two blend systems are less negative than that of the PMMA/PVDF blend system, showing that the incorporation of C-60 reduces the ability of carbonyl groups of PMMA to interact with PVDF. (C) 2000 John Wiley & Sons, Inc.