OBJECTIVES: The objective of this study was to analyze the costs of septic shock in 2012 for England, Wales and Northern Ireland. METHODS: We analyzed length of stay and organ support of 20,549 adult septic shock patients. Septic shock was defined as severe sepsis including the presence of cardiovascular organ dysfunction. Data derived from the Case Mix Programme Database. This is the national, comparative audit of patient outcomes from adult critical care coordinated by the Intensive Care National Audit & Research Centre (ICNARC). These analyses were based on data from 136,880 admissions to 205 adult, general critical care units (CCU) based in NHS hospitals geographically spread across England, Wales and Northern Ireland. Unit costs were obtained from the National Schedule of Reference Costs 2012-2013. RESULTS: There were 22,081 admissions to CCU, with an average duration of 7.6 days. At a cost per day of £1044, this adds up to £175.2 million. There were 14,471 admissions to a post-unit discharge location (23.3 days, £240/day). Total ward cost is thus about £80.9 million. Renal and advanced respiratory support was required by 4,440 and 13,797 individuals, respectively (both cost £285/day). With an average duration of 5.4 days for renal and 7.7 days for respiratory support, the total costs amount to £6.8 million and £30.3 million, respectively. Therefore, the total cost of septic shock is estimated to be around £293.2 million. CONCLUSIONS: With annual costs of nearly £300 million, it is evident that septic shock patients pose a heavy burden to the national healthcare system. These patients require lengthy hospital stays, as well as substantial renal and respiratory support. Adding drug costs, societal costs, as well as Scottish data, would increase the total costs even further. Septic shock is a costly disease and every effort should be made to reduce this burden to the patients, hospitals and society.