The effects of pressure (0.1-450 MPa) on enol-keto tautomerization reaction in salicylic acid (SA) have been investigated by steady-state absorption, fluorescence emission, and excitation spectroscopy. In dilute solutions, the emission intensity of the keto form of the monomer shows marked increase with pressure. In concentrated solutions, where only dimers are present, only a very small increase in the fraction of the keto form of the dimers is observed by applying high pressures. A possible reaction, mechanism for such a behavior is discussed.