This paper reports on detailed studies on the hydrosilylation of alkenes and alkynes with silsesquioxane (HSiMe2O)(i-Su)(7)Si8O12, catalyzed by Pt, supported on a styrene-divinylbenzene copolymer (Pt/SDB). The obtained results clearly indicate that Pt/SDB was a very efficient catalyst, characterized by high TON in the hydrosilylation of a wide spectrum of reagents. The heterogeneous character of the catalyst permitted reuse up to 20 times. The selectivity of all the hydrosilylation reactions was very high, regardless of the catalyst concentration. Pt/SDB is the first example of a heterogeneous catalyst being used for the functionalization of silsesquioxane (HSiMe2O)(i-Bu)(7)Si8O12. Under the tested conditions it was found to be more effective than commercially available and industrially applied Pt catalysts supported on activated carbon, making it one of the most versatile and potentially interesting heterogeneous systems in hydrosilylation reactions. (C) 2018 Elsevier Inc. All rights reserved.