In the crystal structure of the title compound, C(27)H(39)N(2) (+)·I(3) (-), the imidazolidinium ring is perpendicular to a mirror plane which bis-ects the cation. The dihedral angle between the imidazolidinium ring and the benzene ring is 89.0 (2)°. The triiodide anion also lies on a mirror plane and is almost linear with an I-I-I bond angle of 178.309 (18)°.