Thermoplastic molding compositions comprising mixtures ofa) 1-99 wt. % of a specific polycarbonate based on dihydroxydiphenylcycloalkanes,b) 1-99 wt. % of other polycarbonate, in particular those based on bisphenol A, andc) 1-95 wt. % of a silicone rubber, in particular silicone graft rubbers,having improved thermal resistance and being suitable for the preparation of shaped articles, and a process for their preparation are being disclosed.