Improved filled silane copolymer compositions resistant to premature crosslinking during compounding and storage but which are readily hydrolyzed and undergo cure in the presence of silanol condensation catalyst are provided. The compositions are comprised of random copolymers of ethylene and vinyltriethoxysilane and contain relatively high levels of particulate fillers. Rubbery ethylene copolymers are included with the silane copolymer to produce compositions with superior physical properties. The invention also relates to the method of crosslinking these compositions by combining the filled silane copolymer compositions with a second component which has a silanol condensation catalyst dispersed in a polymer resin.