This paper focuses on the thermodynamic study of solution of aromatic amino acid l-tryptophan in water. Free energy, its enthalpic and entropic terms, heat capacity of solution are computed in a wide temperature range using the combination of calorimetric data and solubility value at the reference temperature via the Gibbs-Helmholtz equation. Solubility values from 283.15 to 343.15 K are also estimated and compared with experimental ones. The results obtained clearly indicate that this approach reproduces very well both thermodynamic functions of solution and solubility values for slightly soluble species.