A self-adhesive organopolysiloxane composition is provided comprising (A) an organopolysiloxane containing at least two silicon-bonded alkenyl groups, (B) an organohydrogenpolysiloxane containing at least two SiH groups, (C) a hydrosilylation catalyst, and (D) an adhesive component obtained by previously mixing (i) a titanium chelate catalyst and/or a tetraorganoxytitanium and (ii) a silane coupling agent and aging the mixture. The composition cures at room temperature or lower temperature while it is fully adhesive to metal and plastic substrates.