The title salt, [Zn(C(2)N(2)H(8))(3)](2)[CdI(4)]I(2), conventionally abbreviated [Zn(en)(3)](2)[CdI(4)]I(2), where en is ethylenediamine, contains discrete [Zn(en)(3)](2+) cations and [CdI(4)](2-) anions with distorted octahedral and nearly tetrahedral geometries, respectively, as well as uncoordinated I(-) ions. The cation and the free I(-) anion lie on twofold rotation axes and the [CdI(4)](2-) anion lies on a -4 axis in the space group I-42d. The structure exhibits numerous weak inter-ionic hydrogen bonds of two types, viz. N-H...I(-)(free ion) and N-H...I([CdI(4)](2-)), which support the resulting three-dimensional framework.