In the title compound, [CdI2(C14H12N2)], the molecule sits on a crystallographic twofold axis. The coordination sphere of the CdII atom is built of two symmetry-equivalent N atoms of one 2,9-dimethyl-1,10-phenanthroline (dmphen) ligand and two symmetry-equivalent I atoms, thus forming a distorted tetrahedral geometry. Inversion-related molecules interact along the c-axis direction by π -π stacking interactions between the phenanthroline ring systems, with centroid-centroid distances of 3.707 (9) and 3.597 (10) Å.