The relationship between competitiveness and environment has been deeply investigated by researchers and practitioners. The available empirical evidence are not consistent and do not allow to state that any strand of research has succeeded over the others. In order to enrich this debate, the present study aims at answer the following question: How can the environmental regulation and practices improve the environmental performance and provide competitive advantages to the targeted firms or adopters? Several research questions have been derived from this: 1. Is a stringent environmental regulation able to positively affect the competitive performance of firms? 2. Has the form of environmental regulation a relevant role in this relation? 3. Are the flexible forms of environmental regulation able to influence the environmental and competitive performance? 4. Which are the effects of environmental practices based on the cooperation between the supply chain actors? In order to answer the above mentioned questions, regression analysis was applied to different datasets, focused on several sectors. Useful recommendations for managers and policy makers emerge.