Hexaaquazinc(II) dinitrate 5-(pyridinium-3-yl) tetrazol-1-ide, [Zn(H2O)(6)](NO3)(2)center dot 2C(6)H(5)N(5), crystallizes in the space group P (1) over bar. The asymmetric unit contains one zwitterionic 5-(pyridinium-3-yl) tetrazol-1-ide molecule, one NO3- anion and one half of a [Zn(H2O)(6)](2+) cation ((1) over bar symmetry). The pyridinium and tetrazolide rings in the zwitterion are nearly coplanar, with a dihedral angle of 5.4 (2)degrees. Several O-H center dot center dot center dot N and N-H center dot center dot center dot O hydrogen-bonding interactions exist between the [Zn(H2O)(6)](2+) cation and the N atoms of the tetrazolide ring, and between the nitrate anions and the N-H groups of the pyridinium ring, respectively, giving rise to a three-dimensional network. The 5-(pyridinium-3-yl) tetrazol-1-ide molecules show parallel-displaced pi-pi stacking interactions; the centroid-centroid distance between adjacent tetrazolide rings is 3.6298 (6) angstrom and that between the pyridinium and tetrazolide rings is 3.6120 (5) angstrom.