In 2002, Partners HealthCare (Partners) launched a strategy to accelerate the use of ambulatory electronic medical records across its network of 6000 physicians. Through focus on quality software products, creation of a system of financial incentives, and active engagement of health system leadership, Partners reached high levels of physician adoption by late 2006. Partners eventually introduced a mandate that made ambulatory electronic medical record use a requirement for all of its physicians. During this multi-year initiative, Partners also focused on the effective use of electronic medical records and introduced a series of tactics designed to optimize the use of these systems. With introduction of the meaningful-use concepts in the Health Information Technology for Economic and Clinical Health (HITECH) Act, Partners will transition its efforts toward this important national priority. Partners' experience offers some unique insights into the process of electronic medical record adoption across a large, diverse health system.