OBJECTIVES: Rheumatoid arthritis (RA) is an important cause of admission to UK hospital wards, although few estimates of the cost implications of RA in the hospital sector exist in the literature. This study presents a method of estimating the hospital burden of RA in England. METHODS: The CHKS hospital dataset contains aggregated, anonymised information on diagnosis, hospital experience, and patient demographics for over 80 million episodes in the UK. The CHKS sample, which covers approximately 55% of UK hospital admissions, was used to describe and assess the impact of RA-related episodes in England. Patients with RA (ICD-10 codes M05, M06) as a primary or secondary diagnosis were analysed for comorbidities, procedures (identified using OPCS-4 codes), length of stay, and for repeat admissions during the year. RESULTS: We identified 10,425 unique patients admitted with primary RA in 2001. These patients had a total of 17,395 separate episodes, 42% of which were day cases. Mean inpatient length of stay was 6.9 days, resulting in 70,305 occupied bed days. At least 1 invasive procedure was undertaken in 74% of episodes. While these were mainly injections and infusions, there were 1,650 joint replacements. From a resource use perspective, the 10% of procedures involving joint replacement accounted for 22% of total occupied bed days. Forty four percent of patients with a primary RA episode also had primary RA episodes in the previous 4 years. A further 15,640 unique patients with secondary RA were also identified, having a total of 28,979 episodes. CONCLUSIONS: Each year, there are over 25,000 unique patients with a RA related episode in England. This represents a substantial resource burden in the National Health Service (NHS). An effective and well-tolerated agent, such as an anti-TNF therapeutic, would help reduce the burden on an already overstretched healthcare sector.