The response of polycrystalline TiB2 to neutron irradiation was investigated. The material was fabricated using isotopically enriched B-11 powders to minimize helium production via the B-10(n, alpha)Li-7 reaction. Neutron irradiation was conducted at temperatures of -200 degrees C and -600 degrees C to a fast fluence of 2.4 x 10(25) n/m(2) (> 0.1 MeV). The material exhibited some swelling, but less swelling at the higher irradiation temperature. No macroscopic damage was observed in the irradiated material, although moderate irradiation-induced microcracking was found in the irradiated TiB2. This study demonstrated improved radiation resistance of isotopically tailored TiB2 compared with natural boron TiB2, which exhibited macroscopic fracture by irradiation.