Foamable compositions comprise (a) at least one normally liquid, unsaturated perfluorochemical blowing agent compound selected from the group consisting of perfluoroolefin compounds, e.g., perfluoro(4-methylpent-2-ene), perfluoroaromatic compounds, e.g., hexafluorobenzene, and perfluorocycloolefin compounds, e.g., perfluorocyclohexene, the perfluoroolefin compounds optionally containing one or more catenary heteroatoms; and (b) at least one foamable polymer or the precursors of at least one foamable polymer. The compositions are useful in preparing polymeric, e.g., polyurethane, foams.