Thermodynamic studies of nucleic acids can provide data of both fundamental and practical significance. The thermodynamic parameters derived can be utilized in the investigation of the strength and nature of molecular forces governing the stability of different conformations in nucleic acids. This information can also help to define the different kinds of secondary structures and thus serves as a basis for the prediction of the overall folding of the tertiary structure of nucleic acids. While many studies have focused on the thermodynamic characterization of nucleic acids with emphasis on the design of the nucleic acid-based diagnostic and therapeutic protocols, this review summarizes the thermodynamic parameters that are useful in the determination of thermochemical properties of nucleic acids.