The cation in the title salt, C(33)H(28)FN(3)OPS(+)·Cl(-), is highly twisted with the phospho-nium group occupying a position almost normal to the central hydroxyl-benzene ring [P-C-C-C tosrsion angle = -100.9 (3)°], and with the hydrazone substituent twisted out of the plane [C-C-C-N torsion angle = 13.1 (4)°]. The fluoro-benzene ring is twisted out of the plane of the adjacent thio-urea residue, forming a dihedral angle of 51.69 (10)°. The configuration about the C=N bond [1.281 (4) Å] is E, the O-H and N-H hydrogen atoms are syn, and in the thio-urea residue, the N-H hydrogen atoms are anti, allowing for the formation of an intra-molecular N-H⋯N hydrogen bond. In the crystal, dimeric aggregates mediated by N-H⋯S bonds are formed, which are linked to the Cl(-) anions by O-H⋯Cl hydrogen bonds. The four-component aggregates are linked into a three-dimensional structure by C-H⋯Cl inter-actions.