This paper examines the status of aboriginal rights to water in the Lower Athabasca River Basin. It starts from the premise that Aboriginal peoples living in the Athabasca oil sands region have constitutionally protected water rights, and inquires whether or not these rights are acknowledged and protected by the Alberta government. In the first part of the paper, we discuss the impacts of oil sands developments on Aboriginal water rights. We first review the sources of negative impacts of development on water resources, as described in the scientific literature, we then outline the effects of such impacts on Aboriginal peoples living downstream from these developments. First Nations have many concerns about the impacts of industrial water use and pollution on water resources, notably on the fish and wildlife populations on which they depend, on their transportation needs and on their health. We identify some of the ways in which they have brought these concerns forward to government. In the second part of the paper, we briefly address governments’ obligations, both substantive and procedural, to ensure the protection of the water rights of Aboriginal peoples. We suggest that the promise of rights recognition and rights protection embodied in section 35 of the Constitution Act, 1982 imposes an obligation on government to actively protect these rights, not only to refrain from infringing them. In the third part of the paper, we examine how the Alberta government is meeting its obligations to First Nations as it allocates and manages the region’s water resources in the Athabasca oil sands region while overseeing the development of oil sands resources. The issues are dealt with under the following headings: water management planning initiatives, approval of oil sands development and monitoring the impacts of industrial development on the Lower Athabasca River system. Of the various water management planning initiatives in the region, we review the following: the Muskeg River Comprehensive Water Management Plan, the Water Management Framework for the Lower Athabasca River, the Athabasca River Watershed Management Plan and the Lower Athabasca Regional Plan. We describe each initiative and assess whether they acknowledge the rights to water of First Nations, and whether they allow for adequate consultation with Aboriginal peoples and accommodation of their rights. Next, we discuss the approval process for oil sands development and ask whether it deals with potential impacts on aboriginal or treaty rights to water. These issues are examined more closely in a case study of the Kearl Oil Sands Project review and EUB decision. Finally, based on a review of the findings of several scientific reports released in the past two years, we briefly examine how government monitors the impacts of industrial development on the Lower Athabasca River system and on the water rights of Aboriginal peoples.