Ischaemic heart disease (IHD) is a significant health problem and is the major cause of death in Rheumatoid Arthritis (RA). It is not clear why RA patients should be more at risk. We studied a cohort of patients with longstanding RA, their same sex siblings and osteoarthritis (OA) controls. The aim was to identify and compare the prevalence of IHD in these 3 populations and if there were any cardiovascular risk factors that may be responsible for any differences found.We found that RA patients died most often of IHD, but unexpectedly so did the OA patients. There was no difference in the prevalence of IHD between the 3 groups. There was also little difference in traditional risk factors between these groups, and subsequent calculations of cardiovascular risk. Factors that are shared between OA and RA subjects should be considered as potential causes.