A cylinder head gasket having at least one plate of soft material and at least one combustion chamber opening, said soft material including predominantly inorganic fibers and/or filling materials connected by binding means and including free OH groups, the soft material is mixed with a first impregnating material comprising a polysiloxane containing reactive hydrogen groups for reaction with the free OH groups of the fibers or filling materials and a second impregnating material which consists of a second polysiloxane of a higher degree of polymerization than the first polysiloxane and which polymerizes with itself as well as with the reactive hydrogen groups of the first polysiloxane, said second polysiloxane forming a stable siloxane structure having more branches than the first polysiloxane.