AbstractThe addition of a series of silicon hydrides: trichlorosilane, methyldichlorosilane, dimethylchlorosilane, phenyl dichlorosilane, and methyl phenyl chlorosilane to esters of long chain unsaturated fatty acids, such as oleic, linoleic acids, and 10‐undecenoic acid, was studied with respect to catalysts, temperature, and solvents. Higher yields were obtained on carrying out the hydrosilylation reactions in the presence of chloroplatinic acid or Pt on C catalysts in bulk without solvent, as compared with peroxide catalysts. The addition reaction with methyl 10‐undecenoate, which has a terminal double bond, gave a higher yield than that with methyl oleate. NMR data of the products from methyl 10‐undecenoate and methyl oleate, as well as their reduction products with lithium aluminum hydride, have shown that, with the former ester, the silyl moiety added exclusively to the terminal carbon atom, while, with the latter, no migration of the silyl moiety to the terminal carbon atom was observed.