A crosslinkable fluororubber composition comprising (A) a polymer of the formula: Z-(Rf-Q).sub.n--Rf-Z wherein n is an integer of at least 1, Rf is a divalent perfluoroalkylene or perfluorooxyalkylene radical, Q is a divalent organic radical, and Z is a monovalent organic radical, having a viscosity of at least 1,000 Pas at 25.degree. C., (B) a reinforcing filler, and (C) a peroxide crosslinking agent is effectively roll milled and experiences minimal changes of viscosity after milling. Molded parts can be produced on a mass scale.