In the title compound, C(19)H(16)NO(4)P, the dihedral angle between the mean planes of the phenyl rings bonded to the P atom is 75.4 (1)°. In the crystal, mol-ecules are linked into chains running along the a axis by inter-molecular O-H⋯O hydrogen bonds. Mol-ecules are further connected into a three-dimensional array by weak C-H⋯O hydrogen bonds.