The aim of this study was to determine the ethnic mix of those patients being pre-operatively screened for sickle cell disease in a London teaching hospital and to determine the rate of carriage of sickle haemoglobin amongst those tested. We retrospectively studied 1879 patients undergoing surgery over a 2-month period. Two hundred and thirteen (11%) were screened for sickle cell disease and of these, 12 (5%) tested positive for sickle cell trait (HbAS). There were no patients homozygous for sickle cell disease (HbSS) or with haemoglobin SC disease (HbSC). Screening rates varied widely in different ethnic groups from 0% of the Chinese population to 85.2% of the Afro-Caribbean population. We conclude that at present there is no coherent pre-operative screening policy for sickle cell disease in our institution. Sickle cell disease poses unique anaesthetic risks and with a rapidly expanding 'mixed race' population high-risk patients are difficult to identify phenotypically. We propose a universal screening policy be implemented in high-risk areas.