The aim of this study was to evaluate the effect of multi-professional full-scale simulation-based education of staff on the mortality and staff awareness of patients at risk on general wards. DESIGN, SETTINGS AND PATIENTS: A prospective before-and-after study conducted on four general wards at Herlev Hospital, Denmark. In the pre-intervention period (June-July 2006) and post-intervention period (November-December 2007), all patients on the wards had vital signs measured in the evening by study personnel, who also asked nursing staff questions about patients with abnormal vital signs. The mortality of patients with abnormal vital signs was registered from the hospital database. Simplified medical emergency team calling criteria were used to define abnormal vital signs.