The title spirocyclic compound (alternative name: 2,2,4,4-tetrachloro-9,9-dimethyl-7,11-dioxa-1,3,5-triaza-2lambda5,4lambda5,6lambda5-triphosphaspiro[5.5]undeca-1,3,5-triene), C5H10Cl4N3O2P3, does not contain alternating long-short P-N bond lengths in the phosphazene ring [P-N 1.559 (2)-1.596 (2) A], as are observed in other analogous spirocyclic compounds. The six-membered phosphazene ring has a chair conformation in the solid state, but a conformational equilibrium in solution is indicated by NMR spectroscopy.