A revolution has occurred in sourcing, known as eSourcing. The business case for eSourcing put forward by A.T. Kearney in this paper is simple and attractive. Early adopters of new eSourcing technologies continue to realise savings of 15+% while improving efficiency and transparency. New tools are constantly developing and becoming more affordable at all levels. The paper examines best practices and how to avoid pitfalls, analysing Fortune 1000 company adoption of eSourcing.