BPO4 was previously synthesized by the solid state reactions of (NH4)(2)HPO4 and B2O3 at 1000 degreesC and was characterized by X-ray powder diffraction and IR methods. We have now succeeded in preparing BPO4 from H3BO3 and P2O5 using hydrothermal synthesis by heating at 160 degreesC for 2 days and obtained a single phase product. We observed that a microwave-assisted synthesis takes only 3 to 5 minutes to transform a solid mixture of (NH4)(2)B4O7. 4H(2)O, and solid H3PO4 Or B2O3 + P2O5 into the crystalline title compound. Its X-ray powder diffraction data and IR spectra were in good agreement with the literature values.