RTV organopolysiloxane compositions comprising (A) a diorganopolysiloxane having hydroxyl or alkoxysilyl groups at both ends, (B) a polyoxypropylene-modified silicone, (C) wet silica, and (D) a silane or siloxane having at least three silicon-bonded hydrolyzable groups have improved sag control and cure at room temperature into products with improved rubber physical properties and durability.