Public purchasing authorities are in a leading position for the introduction, promotion and development of green procurement. Indeed, the public sector can influence green procurement both by designing suitable policies and by driving 'green' markets through the significant share of public purchases on GDP. The European Commission (EC) has emphasized the importance of cost-efficient GPP and, in compliance with the EU’s Integrated Product Policy (IPC), Member States have been encouraged to devise national action plans. As a result, many countries have already adopted steps in the direction of greening public purchases. The aim of our paper is twofold: first, we focus on the state of the art in terms of the EU and Italian Legislation; then, we highlight open questions related to crucial issues in GPP implementation, with a particular attention to the design of green tenders and awarding criteria to account for environmental quality in public purchasing procedures.