Abstract Benefit sharing as envisaged by the 1992 Convention on Biological Diversity (CBD) is a relatively new idea in international law. Within the context of non-human biological resources, it aims to guarantee the conservation of biodiversity and its sustainable use by ensuring that its custodians are adequately rewarded for its preservation. Prior to the adoption of the CBD, access to biological resources was frequently regarded as a free-for-all. Bioprospectors were able to take resources out of their natural habitat and develop (...) commercial products without sharing benefits with states or local communities. This paper asks how CBD-style benefit-sharing fits into debates of justice. It is argued that the CBD is an example of a set of social rules designed to increase social utility. It is also argued that a common heritage of humankind principle with inbuilt benefit-sharing mechanisms would be preferable to assigning bureaucratic property rights to non-human biological resources. However, as long as the international economic order is characterized by serious distributive injustices, as reflected in the enormous poverty-related death toll in developing countries, any morally acceptable means toward redressing the balance in favor of the disadvantaged has to be welcomed. By legislating for a system of justice-in-exchange covering nonhuman biological resources in preference to a free-for-all situation, the CBD provides a small step forward in redressing the distributive justice balance. It therefore presents just legislation sensitive to the international relations context in the 21st century. (shrink)