Detailed study of the nature of weak coordination K-O interactions and strong O-H···O hydrogen bonds and estimation of their energy in a potassium hydrophthalate crystal have been performed on the basis of the topological analysis of the electron density distribution function, obtained from precise X-ray diffraction study at 100 K (R1 = 0.0110), within Bader’s “Atoms in Molecule” theory. It is shown that the charge transfer accompanying the formation of cation···anion associates in the crystal is only 0.05 e.