Over a 6-month period, all patients admitted to the Royal United Hospital, Bath, with acute ischaemic heart disease were prospectively followed for the period of their hospital stay. Strict admission and discharge criteria were defined for the Coronary Care Unit (CCU), so that groups of patients could be identified in which the treatment was not ideal. The mortality in the groups of patients who were admitted to the CCU without delay and for an appropriate length of time was 5.1% (18/355). It was significantly higher overall in the groups of patients who were either not admitted (14.3%, 4/28) or whose admission was delayed (17.4%, 4/23). The results underline the importance of the provision of adequate coronary care facilities.