A versatile two-step method has been developed that allows linking of biomolecules covalently to hydrogen-terminated group-IV semiconductors by means of epoxy-alkenes. First, the terminal C==C double bond of the alkene forms a covalent bond with the silicon, germanium, or diamond surface by UV-mediated hydrosilylation. The terminal oxirane moiety then reacts with the biomolecule. As a model system, we investigated the attachment of an esterase B to a Si(111) surface by means of the linker molecule 1,2-epoxy-9-decene. Samples were characterized by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy. The immobilized enzyme retained its activity and exhibited good long-term stability.