Slurry management plays a crucial role in the integration of crop and livestock production systems and the interaction between agriculture and the environment. This paper presents the comparison by Life Cycle Assessment of two scenarios of collective excess slurry management: The Transfer of slurry and its deep injection to crop land vs its Treatment in a collective biological treatment plant. The study is based on a case in Western France, where a group of farmers needs to dispose of more than 7000 m3 of excess slurry. The overall environmental performance of the Transfer scenario is better than that of the Treatment scenario. The two scenarios are similar for Climate Change, whereas Eutrophication and Acidification are twice as large for Treatment relative to Transfer. Non-renewable Energy Use is 270 MJ m-3 for Treatment, whereas the Transfer scenario results in a net energy savings of 110 MJ m-3 due to the substitution of mineral fertilisers by slurry application to crops.