The hydrosilylation of mono- and di-alkenyl sulphides of the type RS(CH 2) n CHCH 2 (R = C 2H 5, CH 2CH, CH 2CHCH 2, C 3H 7, n = 0, 1 and 4) by triethyl- and triethoxy-silane, catalyzed by H 2PtCl 6·6 H 2O, (Ph 3P) 3RhCl and (PhCN) 2PdCl 2·Ph 3P, has been studied. The addition of hydrosilane to the double bond of alkenyl sulphide leads to a mixture of two isomeric monoadducts. The hydrosilane can cleave the CS bond of the initial sulphides giving the corresponding derivatives of thiosilanes, X 3SiS(CH 2) n CHCH 2 (X = C 2H 5, C 2H 5O). Hydrosilylation of alkenyl sulphides is accompanied by some side reactions such as dehydrocondensation, reduction and polymerization. The effect of the catalyst nature, the structure of hydrosilane and alkenyl sulphide on the reaction route has been investigated.