The title compound, [HP(CH3)3][IrCl4{(H3C)3P}2], consists of a trimethylphosphonium cation and a tetrachloridobis(trimethylphosphane)iridate(III) anion. The anion has an octahedral arrangement of ligands, with the trimethylphosphane groups occupying trans positions. The IrIII atom sits on an inversion center with one P(CH3)3 ligand and two chloride ligands in the asymmetric unit. The trimethylphosphonium cation is disordered about a twofold rotation axis. The title compound is the first structurally characterized tetrachloridobis(phosphane)iridate complex.