Problem: In-hospital cardiac arrest often represents failure of optimal clinical care. The use of medical emergency teams to prevent such events is controversial. In-hospital cardiac arrests have been reduced in several single centre historical control studies, but the only randomised prospective study showed no such benefit. In our hospital an important problem was failure to call the medical emergency team or cardiac arrest team when, before in-hospital cardiac arrest, patients had fulfilled the criteria for calling the team. Design: Single centre, prospective audit of cardiac arrests and data on use ofthe medical emergency team during 2000 to 2005. Setting: 400 bed general outer suburban metropolitan teaching hospital. Strategies for change: Three initiatives in the hospital to improve use of the medical emergency team: orientation programme for first year doctors, professional development course for medical registrars, and the evolving role of liaison intensive care unit nurses. Key measures for improvement: Incidence of cardiac arrests. Effects of the change: Incidence of cardiac arrests reduced 24% per year, from 2.4/1000 admissions in 2000 to 0.66/1000 admissions in 2005. Lessons learnt: Medical emergency teams can be efficacious when supported with a multidisciplinary, multifaceted education system for clinical staff.