A new crystal of 2-aminopyridine phosphate (NC₄H₄NH₂)H₃PO₄ has been grown and its x-ray structure and physical properties were studied. At room temperature the crystals are monoclinic, space group C2/c. The flat 2-aminopyridine cations are hydrogen bonded to the anionic [PO₄ ] groups. The interesting feature of the crystal structure is the three-dimensional network of hydrogen bonds including, among others, two strong, symmetrical O H, H O interactions with disordered proton locations. Symmetrically related PO₄ anions linked through these protons form infinite (PO₄)_∞ chains along the crystal a-axis. The anomalies in the temperature dependence of the electric permittivity showed that the crystal undergoes ferroelectric phase transition at T_c = 103.5 K. The spontaneous polarization takes place along the crystal a-axis, being parallel to the chains of the hydrogen-bonded PO₄. The disordered protons, thermally activated at room temperature, can be frozen at their positions in the ferroelectric phase. The order–disorder continuous type of the transition has been evidenced on the basis of the temperature dependences of electric permittivity and spontaneous polarization measurements.