A silicon composition as described below, which is suitable for sealing semiconductors, is provided. The silicone composition comprises (A) a diorganopolysiloxane with at least two alkenyl groups bonded to silicon atoms, (B) an organohydrogenpolysiloxane with at least two hydrogen atoms bonded to silicon atoms, (C) an adhesion imparting constituent, (D) a platinum group metal based catalyst, and (E) a compound represented by a general formula (1): ##STR1##

(wherein, R¹ represents a monovalent hydrocarbon group of at least 10 carbon atoms, which may contain a hydroxyl group or an ether linkage). The silicon composition displays excellent adhesion to semiconductor chips, and enables the production of a semiconductor device with superior resistance to moisture permeation.