The current competitive environment within the construction sector is increasingly difficult and challenging, leading all the main players to increase their focus and efforts upon procurement strategies and policies. Therefore, procurement practice is important in order to effectively perform and close out the construction process and meet stakeholders' needs. Starting from a deep analysis of procurement processes framed within the project life cycle, the research proposed the prequalification phase as a selection strategy necessary to identify the contractor. In order to select the project delivery system most suitable to the customer and the project to be developed, an operating procedure has been proposed, allowing who deals with procurement better ruling the purchasing processes. In the proposed procedure, each activity is defined through a general overview, the execution process and its tools. The outputs of the study are also sample documents and model forms that can be easily utilized assisting the procurement phase. Thus, since the procurement process has assumed increasing importance in the strategic planning of the construction industry, the aim of the research is to provide a prequalification method necessary to select the most suitable contractor before the tender, in order to reduce any risks during the entire construction process.