ITQ-13, a tridirectional medium-pore zeolite containing 9- and 10-member-ring pores, has been successfully synthesized by a hydrothermal method. The catalytic performance of Mo-ITQ-13 is worse than with Mo-ZSM-5 in the methane aromatization reaction. It has been shown that 9-member-ring channels favor coke and are a disadvantage in methane non-oxidative aromatization.