With this paper we intend to offer some of the conclusions of the Thesis with which we had pursued our PhD in Philosophy at the National University of Rosario (UNR).The aim of our doctoral research was to analyze the commentaries that Cardinal Cajetan (Thomas de Vio) made to the notion of justice, exposed by Thomas Aquinas in S. Th. II-II, qq. 57-62. By doing this we pursued the objective of our study, which was to show that Cajetan?s definition of this virtue differs from the one held by Aquinas. To do so, we adopted the Leonina editions of the works of Saint Thomas, which includes the glossa of the Princeps Commentatorum.We present with this work, then, some of our partial conclusions, as well as the most important advances we had made.