The paper analyses how the “culture of suspicion” hinders the contractual activity of public administration. The “culture of suspicion” consists in the perception that every negotiation procedure is the harbinger of crimes and/or “maladministration”. The effects of this “culture of suspicion” consist of immobilism and inertia, since they inhibit the full recourse to discretionary and efficient actions, so that public officials avoid choices which can be risky in terms of penal, civil and administrative liability. In this context, the idea of contracts awarded by central purchasing bodies (contracting authorities) can play a crucial role. This is because the attribution to a single body of the competence to buy goods and services on the market, in addition to achieving positive “economies of scale”, can also increase the professionalism of the public officials operating within the contracting authorities and promote the transparency of tendering procedures. The paper focuses also on a critical analysis of the current regulatory framework, both at the national and EU level, trying to evaluate and propose necessary reforms and improvements.