In 1995, a medication error at Boston's Dana-Farber Cancer Institute (DFCI) that received intense media scrutiny, transformed the Institute in many ways. Primarily, patient safety became a major priority that led to Institute-wide organizational learning. As a result, DFCI emerged as a national leader in the patient safety movement. A key factor believed to have contributed to this effort was the use of a multidisciplinary team approach to identifying and preventing errors, with the patient and family members as an integral part of the team. In addition to teamwork, other activities included implementing a new chemotherapy order entry system, transforming the culture to a non-punitive one where staff are encouraged to openly discuss errors and safety issues, and introducing a root cause analysis process for error/near miss investigations. Several guiding principles served as the foundation for the efforts including: 1) systems, not individuals, must be the focus of safety initiatives; 2) organizations must create a non-punitive culture; 3) changes must be hard-wired into systems; and 4) multidisciplinary participation, including patients and families, is critical to success.