Green Certificates are usually described as negotiable instruments or commercial papers. The Italian legal system identifies Green Certificates as rights but, due to the ambiguity of the definition, their juridical nature remains uncertain. This reverberates on the functioning of the Green Certificates market and on the enforcement of the relevant norms. This paper discusses the actual legal nature of Green Certificates in Italy and concludes that they should be regarded as goods. This means that private law instruments apply in their market transactions, with consequent implications on the policy side. (C) 2011 Elsevier Ltd. All rights reserved.