The miscibility of C-60-containing poly(2,6-dimethyl-1,4-phenylene oxide) (PPO-C-60) with several styrenic polymers was studied. PPO-C-60 samples containing 6.9 and 19.5 wt% C-60 are miscible with polystyrene, poly(p-methylstyrene), poly(alpha-methylstyrene) and poly(styrene-co-p-methylstyrene) based on the optical clarity of the blends and the single glass transition temperature criterion. However, the two PPO-C-60 samples are miscible with poly(styrene-co-acrylonitrile) when the acrylonitrile content of the copolymer is 6.3 wt% or less.