The cholera outbreak brought to Haiti in 2010 as a consequence of wastewater mismanagement in one of the UN Stabilisation Mission’s camps drew attention to the concrete material footprint of UN peace operations. Since the 2000s, UN peacekeeping missions have been increasingly confronted with environmental challenges. Multiple transformations in terms of norms and practices resulted from these environmental concerns. Drawing on data generated through interviews and participant observation, this article explores how environmental concerns are integrated in UN peacekeeping operations and develops a two-fold argument. First, I argue that the inclusion of environmental concerns in UN peacekeeping relies on the environmentalization of peacekeeping practices. It consists of heterogeneous elements – standards, expertise, training, mainstreaming, equipment management – which focus on the ecological footprint of UN peacekeeping. Second, I show that environmentalizing peacekeeping contributes to the securitization of the environment. By understanding the dynamics of inclusion of environmental concerns, this article sheds light on one of the ways through which emerging issues broaden and widen UN peacekeeping practices.