BACKGROUND: The Deprivation of Liberty Safeguards (DoLS), introduced into the Mental Capacity Act 2005, were fully implemented on 1 April 2009 in England and Wales. The government estimated 20 000 assessments for DoLS at a cost of £600 per assessment. Aims To estimate the costs likely to be incurred with the implementation of DoLS in England. METHOD: The cost of conducting a single DoLS assessment was estimated using resource-utilisation data ascertained from 37 professionals, secretarial staff and independent mental capacity advocates involved with DoLS assessments in six diverse local DoLS offices. RESULTS: The estimated average cost of a single DoLS assessment was £1277. CONCLUSIONS: The estimated average cost of a single DoLS assessment was significantly higher than the £600 estimated by the government. However, the allocated budget, based on 20 000 estimated DoLS assessments in the first year of its implementation, is likely to be adequate because a significantly lower number of assessments (only 5200) were conducted in the first 9 months after its implementation.