The cohesion or solubility parameter represents a substance's cohesive energy density or the energy needed to vaporize one mole of a substance and expand the vapor until molecules cannot interact. Cohesion or solubility parameter study and its practical applications in multiple areas of human activity has attracted the attention of many scientists in the academy and industry . Several published theoretical articles attempted to extend the predictability of Hansen parameters beyond the solubility of polymers 62 , 63 . We found no attempts in the literature to find the relationship between the experimentally determined cohesion parameters (HSP) and DNA denaturation in different solvent/cosolvent compositions. One of the purposes of the present article is to find such a relationship. According to its definition, the cohesion parameter is part of the enthalpy of solubility processes and is used to find/define the boundary for solute-solvent solubility.