In the eyes of most companies, decision support tools are related to tangible or measurable issues, such as Net Present Value (NPV) and Internal Rate of Return (IRR) of investment. Such straightforward indicators are the most adopted solutions to show the financial value that each project brings to the company and shareholders. They also check if a project is consistent with the attractiveness rate proposed for the desired growth. However, the investment analysis in many sectors has been taken into account subjective criteria that are not fully measurable by classical economic tools. In the petroleum refining industry the situation is similar because there are governmental, environmental and political factors that influence the decision-making. Therefore, due to the difficulty of expressing the reality in ranking and selecting projects only using traditional tools, this work was developed in order to provide insights on ranking a group of five projects belonging to a large investment portfolio from an oil company. To make such work operational, it was taken into account several criteria that reflect the concerns of the decision makers involved, and it was adopted the AHP method (Analytic Hierarchy Process) as a tool to perform the rank of the projects under a multicriteria analysis. The key finds from such application were that the results reflect the preferences of the decision makers, and show the alignment with strategic goals and the legal requirements as the most relevant criteria, along with the project of diesel quality in the southeast region as the major investment priority at the present time.