The paper, Lessons from EnvironmentalMainstreaming: Towards Environmental Sustainability wascompleted December 2010. The core message of the 2001 WorldBank Environment Strategy was to support developingcountries in their efforts to mainstream or integrateenvironmental considerations into activities of the economicsectors (energy, water supply, urban development, ruraldevelopment, transport, etc.). The Strategy sought to movebeyond mitigating environmental impacts of development,embodied in the Bank s environmental safeguards policies,towards a progressive adoption of environmental aspectsacross Bank services. The tools suggested to help the Bank sclient countries achieve such integration were upstreamanalytical and advisory inputs for sector decision-makingand for improving the understanding of poverty-environmentlinkages. As an input to the new 2010 World Bank EnvironmentStrategy, this paper aims at assessing the degree ofmainstreaming environmental activities in Bank activities,reviewing how this was achieved, and determining whether ithelped countries in their environmental management efforts.Furthermore, since the 2010 Environment Strategy seeks tomove the World Bank Group towards environmentalsustainability, the paper recommends illustrations ofenvironmental outcome indicators as part of the 2010Strategy's results framework.