The UK tax credit system was designed to stimulate low-income workers and families with children to work and alleviate their financial hardship. However, in practice its governance technologies seem to be ill-equipped to engage with the ‘lived reality’ of its target public and drastically redefine the lives of claimants. This paper conducts a critical discourse analysis of the tax credit system by combining several theoretical and methodological approaches. First, it draws on the work of Foucault, Rose, and Miller on accounting as a technology of governance to understand the wider socio-political discourse of the tax credits system and the use of accounting rhetoric and calculative practices in it. Second, it uses ethnographic and grounded theory methods to explore the experiences and encounters of tax credits claimants and HMRC officials. Early findings suggest that tax credit claimants are not financially better off by working more hours and are perversely held accountable for overpayment problems created by the HMRC. This paper finds that the accounting technologies of the tax credit system dehumanises claimants by transforming claimants from being subjective, emotional human beings who live stressful and busy lives to standardised abstract objects who are all treated in the same way. This paper argues that the tax credit system, as an accounting technology of Government, is not a welfare system but is a governing system which monitors, assesses and sanctions citizens. These findings point out how the tax credit system underlies the targeting of tax credit claimants and sustains a neo-liberal discourse of private responsibility for financial hardship through its accounting technologies and everyday practices.