The present study examines how the question of reparation for environmental damage that occurred during the operation of economic and industrial activities has been dealt with in international law and within the European Union legal system. In particular, the thesis endeavours to provide a comparative analysis of the Directive 35/2004/EC on Environmental Liability with regard to the Prevention and Remedying of Environmental Damage with relevant developments on the international level, and tries to define a conceptual framework with which to examine the relationship between the two legal systems. The need to find concrete and effective responses to the problem of environmental degradation has prompted the recourse to a plethora of legal instruments and determined the emergence of different approaches to the question of environmental liability. More specifically, the integration of environmental concerns into liability systems has determined a revision of the ultimate goals traditionally assigned to liability and an adjustment of its classic structures to new realities. Therefore, the overall legal framework on environmental liability in Europe and on the international level is gradually evolving towards the coexistence of traditional schemes of civil liability with new regulatory models for prevention and reparation of environmental damage.  The starting point for the analysis is the recognition that appropriate and effective responses to the problem of environmental harm require a coherent and coordinated application of different legal tools, private and public, international and European. By looking at the interface between international law and EU law in the field of environmental liability, this study identifies different conceptual and regulatory approaches to the question of prevention and reparation for environmental damage. It explores potential synergies and interactions among them with a view to achieving the ultimate goal of providing effective responses to the problem of environmental harm.