Triethylammonium dicitratoborate monohydrate (C2H5)(3)NH[(C6H6O7)(2)B]center dot H2O (I) was synthesized for the first time. Its crystal structure was solved from single crystal X-ray diffraction data (a = 9.7821(2) A..., b = 23.2196(4) A..., c = 10.0705(2) A...; beta = 90.97(1)A degrees; Z = 4, space group P2(1)/n, 5091 reflections with R (int) = 0.0219; R1 = 0.0733). The structural units of crystal I (the large dicitrato borate anion with a spirane structure, the triethylammonium cation, and the crystal water molecule) form a layered packing with a system of seven O-H...O and N-H...O hydrogen bonds.