Hydrosilylation of o-allylstyrene with trichlorosilane in the presence of 0.3 mol % of a palladium catalyst bearing triphenylphosphine gave trans-1-methyl-2-(trichlorosilylmethyl)indan, 1-(2-(2-propenyl)phenyl)-1-trichlorosilylethane, and 1-(2-((E)-1-propenyl)phenyl)-1-trichlorosilylethane. The reaction of styrene with trichlorosilane gave a quantitative yield of 1-phenyl-1-(trichlorosilyl)ethane while allylbenzene did not give silylation products under the same reaction conditions. These results show that the hydropalladation process is operative in the hydrosilylation of styrene derivatives with trichlorosilane catalyzed by palladium-phosphine complexes.