In title salt, C(38)H(34)P(2) (2+)·2IO(4) (-), the P atoms of the dication and the I atoms of the periodate anions are each in a slightly distorted tetra-hedral environment. In the dication, the two -P(C(6)H(5))(3) groups adopt a gauche conformation with respect to each other. In the crystal, several C-H⋯O hydrogen bonds between the cations and anions lead to a two-dimensional arrangement along (101).