The title compound, C(19)H(14)ClO(2)PSe, was obtained in the reaction of the diphenyl-monoseleno-phosphinic acid ammonium salt with 4-chloro-benzoyl chloride. The dihedral angle between the P-bonded aromatic rings is 72.64 (14)°. Packing of the mol-ecules in the crystal is reinforced by π-π stacking inter-actions between two inversion-related 4-chloro-benzene rings [centroid-centroid separation = 4.189 (2) Å] and a C-H⋯O interaction also occurs.