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A homochiral helical three-dimensional coordination polymer, poly[[(2-acetato-3O,O':O)(hydroxido-O)(4-5-nicotinamido-1H-1,2,3,4-tetrazol-1-ido-5N1,O:N2:N4:N5)(3-5-nicotinamido-1H-1,2,3,4-tetrazol-1-ido-4N1,O:N2:N4:N5)dicadmium(II)] 0.75-hydrate], {[Cd2(C7H5N6O)2(CH3COO)(OH)]·0.75H2O}n, was synthesized by the reaction of cadmium acetate, N-(1H-tetrazol-5-yl)isonicotinamide (H-NTIA), ethanol and H2O under hydrothermal conditions. The asymmetric unit contains two crystallographically independent CdII cations, two deprotonated 5-nicotinamido-1H-1,2,3,4-tetrazol-1-ide (NTIA-) ligands, one acetate anion, one hydroxide anion and three independent partially occupied water sites. The two CdII cations, with six-coordinated octahedral and seven-coordinated pentagonal bipyramidal geometries are located on general sites. The tetrazole group of one symmetry-independent NTIA- ligand links one of the independent CdII cations into 61 helical chains, while the other NTIA- ligand links the other independent CdII cations into similar but unequal 61 helical chains. These chains, with a pitch of 24.937 (5) Å, intertwine into a double-stranded helix. Each of the double-stranded 61 helices is further connected to six adjacent helical chains through an acetate 2-O atom and the tetrazole group of the NTIA- ligand into a three-dimensional framework. The helical channel is occupied by the isonicotinamide groups of NTIA- ligands and two helices are connected to each other through the pyridine N and carbonyl O atoms of isonicotinamide groups. In addition, N-HO and O-HN hydrogen bonds exist in the complex.