The National Cardiac Arrest Audit (NCAA) is a clinical audit of in-hospital cardiac arrest that aims to improve resuscitation care and outcomes in the United Kingdom (UK). NCAA is a collaboration between the Resuscitation Council (UK) and the Intensive Care National Audit & Research Centre (ICNARC) and is subscription-based. Inclusion criteria are all individuals (excluding neonates) receiving chest compressions and/or defibrillation and attended by a hospital-based resuscitation team (or equivalent) in response to an emergency call. Of 136 hospitals now participating, 83 had data for the period 1 April 2011 to 31 March 2012 and were included in the analysis. These hospitals were distributed across England and Wales and 43% were teaching hospitals. A total of 8,867 in-hospital cardiac arrests were reported for 8,499 patients (range 6 to 360 across individual hospitals). Mean age was 73 years and 57% were male. Of the 7,936 (90%) arrests with a known presenting rhythm, 4,201 (53%) presented with PEA, 2,157 (27%) asystole, 1,032 (13%) VF, 470 (6%) VT and 76 (1%) with bradycardia with a pulse. Overall, return of spontaneous circulation (ROSC) for > 20 minutes was achieved following 4,006 (45%) arrests and 20% survived to hospital discharge. ROSC for > 20 minutes and hospital survival varied substantially by presenting rhythm and by hospital. For example, after VF arrest, overall, 48% of patients survived to hospital discharge but this varied considerably across hospitals (Figure 1). These data indicate the need for an accurate, multivariable risk model, incorporating presenting rhythm and other important risk factors, to be able to assess performance across UK hospitals.