GPC-MALS in alpha,alpha,alpha-trifluorotoluene mobile phase has been employed successfully to determine molecular weight and molecular weight distribution for highly fluorinated (hydrocarbon insoluble) polymers. This technique was used to characterize several fluoroalkyl acrylic and fluorolkyl methacrylic polymers, perfluoropolyethers, hydrocarbon polymers such as polystyrene and poly(n-butyl acrylate), and their block copolymers with excellent results. The current report is focused on characterization of poly(1,1,2,2-tetrahydroperfluorodecyl acrylate) and polystyrene as representative materials of interest. Results for samples ranging from 1000 to 1 600 000 g/mol were in excellent agreement with independent measurements determined by H-1 NMR end group analysis, GPC in hydrocarbon solvents, and those provided by the supplier, as applicable.