The effect of employing severity scores to identify severe community-acquired pneumonia (SCAP) cases for early aggressive resuscitation is unknown. Optimising pre-intensive care unit (ICU) care may improve outcomes in patients at risk of SCAP. We conducted a before-and-after study of patients classified into control and intervention groups (January 2004 to December 2007 and January 2008 to December 2010, respectively). Our intervention was two-pronged, using the 2007 Infectious Diseases Society of America (IDSA)/American Thoracic Society (ATS) minor criteria to identify SCAP for aggressive emergency department resuscitation. Patients with SCAP, defined as those with three or more IDSA/ATS minor criteria, were targeted. Differences in mortality, triage and compliance with emergency department resuscitation were compared between the groups. The hospital mortality rate was lower in the intervention versus the control group (5.7% versus 23.8%, p<0.001). On multivariate analysis, the intervention group was associated with lower mortality (OR 0.24, 95% CI 0.09-0.67). ICU admission rates decreased from 52.9% to 38.6% (p=0.008) and inappropriately delayed ICU admissions decreased from 32.0% to 14.8% (p<0.001). There was increased compliance with the aggressive resuscitation protocol after the intervention. A combined intervention, using a pneumonia score to identify those at risk of SCAP early and an aggressive pre-ICU resuscitation protocol may reduce mortality and ICU admissions.