The miscibility behaviour of poly(2-fluoroethyl methacrylate) (P2FEMA) and poly(1,1,1,3,3,3-hexafluoroisopropyl methacrylate) (PHFPMA) with various polymethacrylates was studied by differential scanning calorimetry and for lower critical solution temperature (LCST) behaviour. Both P2FEMA and PHFPMA are miscible with poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA) and poly(tetrahydrofurfuryl methacrylate) (PTHFMA), but are immiscible with poly(n-propyl methacrylate) (PnPMA), poly(isopropyl methacrylate) (PiPMA), poly(n-butyl methacrylate) (PnBMA) and poly(cyclohexyl methacrylate) (PCHMA). Phase separation could be induced by heating for blends of P2FEMA with PMMA and PEMA. For PHFPMA, only PHFPMA/PEMA blends showed LCST behaviour. The miscibility behaviour of P2FEMA and PHFPMA is similar to that of poly(2-chloroethyl methacrylate).