Titanate nanotubes (TiNT) surface modified with (3-aminopropyl)trimethoxysilane were employed as a support for covalent immobilization of horseradish peroxidase (HRP) by using 1,4-benzoquinone as a coupling agent. Composite film-electrodes consisting of HRP-modified TiNT embedded into the porous carbon powder/Nafion matrix were fabricated and their applicability in direct bioelectrocatalytic reduction of H 2 O 2 and H 2 O 2 biosensing were investigated. An efficient direct electron transfer between the immobilized HRP molecules and the electrode was observed in the presence of H 2 O 2 at potentials lower than 600mV (vs. Hg/Hg 2 Cl 2 /3.5M KCl). For the HRP–TiNT-modified electrodes polarized at 0mV, a linear dependence of the bioelectrocatalytic current on the concentration of H 2 O 2 was observed up to the concentration of H 2 O 2 equal to 10μM, with the sensitivity of (1.10±0.01)AM −1 cm −2 and the detection limit of 35nM.