A cetyltrimethylammonium bromide (CTAB)-assisted hydrothermal method was applied to prepare beta-BaB2O4 nanowires using Ba(NO3)(2) and NaBH4 as reactants. After subsequent annealing in air at 700 degrees C, beta-BaB2O4 nanowires with a diameter of 10-20 nm and a length up to several micrometers were obtained. The characterization results indicate that beta-BaB2O4 nanowires are single crystalline with the preferential growth direction along [113].