Crystals of bis(3-ammoniopropyl)ammonium sulfate monohydrate: (C6H20N3)SO4HSO4.H2O were prepared and grown at room temperature by slow evaporation method. Crystal structure, IR spectroscopy and thermal behaviour were investigated. The structure of this new organic sulfate was determined by single crystal X-ray diffraction technique. The title compound crystallizes in the orthorhombic space group Pbcn. It is composed of dimers resulting from the association of SO4 2- and HSO4 -anions with water molecules. The inorganic arrangement shows cavities where the organic molecules are located to create a three-dimensional framework