This paper presents a model for Public Contracting Authorities to quantify procurement performance benefits that can be achieved by adopting e-procurement. It has been found that e-procurement could generate positive impacts, especially on the efficiency, effectiveness, dematerialization, competitiveness and transparency impact dimensions.Adopting e-procurement in the public sector is far more than just a technological challenge, it embodies a large scale change management effort to create a more efficient procurement culture. Using the performance measurement approach herewith presented helps to tackle this challenge, stimulating the effective use of e-procurement solutions.Measuring how e-procurement is contributing to optimize public expenditure by increasing organizational performances, can help to overcome the resistance to change. Plus, this model can be used to strengthen stakeholder accountability of both Contracting Authorities and public eprocurement service providers.The model has been consistently tested over the last 4 years, the case study is herewith exposed. The model can be applied in different context, therefore method and practical recommendations are also provided.