The purpose of this thesis is to propose a standardization model for the purchase process of legal professional services leveraging e-Procurement and to validate the benefits brought by the implementation of both, an e-Procurement tool and a new procurement process. The hypotheses of this thesis are applicable to the procurement of legal professional services of large companies with a central legal department in charge of managing the relations with different legal firms (legal services suppliers). The information presented was gathered in a large global manufacturing company with strong presence in Europe. The procurement of legal professional services throughout the entire organization was analyzed and validated by central legal department based in the headquarters. An innovative model for the procurement of the legal services has been proposed based on different findings in the current literature. Also, a model developed by Ronchi et al. was leveraged to quantitatively measure the benefits brought by the implementation of e-Procurement. The model was implemented in the organization with the help of central purchasing and legal departments. The results showed it is possible to standardize the operative procurement of legal professional services for end-users to perceive the same process as the one used for direct purchases of office supplies. In order to accomplish this, some roles and an important transformation within the organization must be carried out. A general model to implement a comprehensive procurement process leveraging e-Procurement is presented in this study. The conclusions are that the specialized procurement literature focuses very little on service procurement standardization and even less in legal professional services or process standardization through e-Procurement, and thus this study and the model introduced might work as a starting point for professional practitioners or academic researchers alike. Further research topics are suggested at the end of this study to continue research on this topic.