Abstract: Fiber-treating compositions are described which durably provide water repellency and oil repellency for the treated fiber. These compositions comprise a siloxane component bearing fluorinated hydrocarbon radicals, unsubstituted hydrocarbon radicals and silicon-hydride atoms, and a dehydrogenation condensation catalyst. Curing of the compositions occurs by a dehydrogenation condensation reaction between the silicon-hydride atoms and/or between the silicon-hydride atoms and the hydroxyl radical of an optionally added hydroxyl-endblocked organopolysiloxanes.