A number of frameworks have been proposed to help organizations manage their IT projects and get the willing benefits, such as Project Management Book of Knowledge, Managing successful programmes, Program management and Managing Benefits from APMG certificate. Even though most of them are prescriptive, evidence has shown that organizations front strong difficulties to adopt them. Hence, this paper present the benefit realization methodology implemented by a public organization to appropriately manage IT/IS project benefits. Based on two case studies from the same organization, we described how the organization have identified desired benefits, defined project outcomes, planned benefit realization, realized benefits and assessed the benefit accomplishment. We have also described which stakeholders should participate in the benefits realization methodology and described their main responsibilities: portfolio management level, program and project level, project sponsor, lead users and change management officers.