The title compound, C(16)H(21)NP(+)·I(-), was obtained by the reaction of Ph(2)PN((i)Pr)P(Ph)N((i)Pr)H with MeI involving cleavage of one of the P-N bonds in diethyl ether. The two phenyl rings form a dihedral angle of 82.98 (5)°. A weak donor-acceptor N-H⋯I inter-action is observed.