This study investigates the market for audit services in the UK National Health Service (NHS). The market has a number of interesting features, including the presence of the Audit Commission as a regulator, appointer and provider of audit services. Following a theoretical overview of audit pricing in the NHS, evidence is provided on the behaviour of private sector auditors in an environment where audit risk characteristics differ from the private sector. The research also investigates, for the first time in the public sector, the relationship between audit fees and non-audit (consultancy) fees. Comparisons are also drawn between audit fees in the public and private sectors in an analysis of audit fees by industry. Despite some key similarities, the study shows that a number of differences exist between private and public sector audit fee models. In particular, we find no evidence of Big 6 (or mid-tier) auditor premiums, but we do find a significant negative relationship between audit and consultancy fees providing support for the 'knowledge spill-over' hypothesis. In addition, the fees charged to trusts appear significantly lower than their private sector counterparts, despite trust auditors having additional duties to perform. Possible explanations for this finding are offered in the paper. Copyright Blackwell Publishers Ltd 2002.