Circumcision remains a common operation, with over 30,000 procedures performed annually in the UK, mostly on children. The British Medical Association has recommended that circumcision should be performed only for medical reasons. Despite this, controversy exists over whether too many circumcisions are being performed. Are patients being exposed to an unnecessary operation? It may be argued that in doubtful cases it is easier to proceed to circumcision on the assumption that the attendant risks are low, but the operation is associated with a definite morbidity and rare deaths have been reported. This review considers the spectrum of complications that may result from circumcision and discusses the possible aetiological mechanisms.