ZnO particles co-doped with boron and fluorine (B, F-ZnO) were prepared by a simple hydrothermal technique. The reaction took place in an autoclave at 200 degrees C for 4 h. Then the particles were annealed at 600 degrees C for 1 h and the characteristics of the particles were investigated as a function of boron (1, 3 and 5 at.%) and fluorine (3 at.%) concentrations in the solution. X-ray diffraction (XRD) measurements showed that doped ZnO particles had hexagonal wurtzite structure for all precursor solutions. Morphological characterization of the particles was done by a scanning electron microscope (SEM) and the results showed that the morphologies of all doped particles had a regular hexagonal shape. Thermal properties of particles were investigated by TG-DTA analysis. The optical measurements reveal that all absorption curves exhibit an observable absorption in the range 320-400 nm, with the absorption edge in between 380 and 375 nm.