OBJECTIVES: Hypoglycaemia is a common adverse event associated with the management of both type 1 and type 2 diabetes.  While many hypoglycaemic episodes can be self-treated, more severe episodes can require emergency treatment and hospitalisation.  The objective of our study was to evaluate the burden of hypoglycaemia on secondary care costs in England.  METHODS: Data captured in Hospital Episode Statistics (HES)* for the period between 2006 and 2009 was analysed to estimate the trends in hospital episodes. The associated costs were estimated using Hospital Resource Group (HRG) tariff prices in England for the respective years. RESULTS: There were a total of 11,330 inpatient spells assigned an HRG for hypoglycaemia in 2009, an increase of 17.0% from 2006 when there were 9,682 inpatient spells.  In 2006 the average inpatient length of stay was 5.7 days, but by 2009 this figure had risen by 21.1% to 6.9 days.  In 2006 the cost of hypoglycaemia due to hospitalisation was £13.57 million.  In 2009 this figure was £16.04 million, representing an 18.2% increase in cost burden.  In 2009 the average inpatient cost was £1635, up 8.7% from 2006 when the average cost was £1504.  Over the four year period 2006-2009 there were a total of 41,717 inpatient spells due to hypoglycaemia at a total cost of £58.44 million.  CONCLUSIONS: Hypoglycaemia represents a significant and increasing burden on hospital care in England. Given current cost constraints in the NHS, prescribers should seek to use medications that reduce the risk of hospitalisation due to hypoglycaemia.