In the last 10 years, the majority of large companies have attempted to install Enterprise Resource Planning (ERP) systems, replacing functional systems with a standardised company-wide system. However, making an ERP system work, we contend, is more than an issue of technical expertise or social accommodation: it is an ongoing, dynamic interaction between the ERP system, different groups in an organisation and external groups, such as vendors, management consultants and shareholders. This paper builds this argument using the example of management accountants in the U.K. based on evidence from a survey and several case studies. Drawing on work by Scarbrough and Corbett, we apply and develop a model, the technology power loop, linking technology, the control of technology and expertise to explain issues of how ERP systems are made to work and how expert groups seek to influence this development. We show, using empirical evidence from a survey and several case studies, that the relationship of accountants and technologies such as ERPs has become increasingly intertwined, but accountants continue to use their position to reshape their professional expertise wherever possible. However, our evidence also shows that neglect in this area allows other groups to wrest control from management accountants and make ERPs work for themselves. © 2005 Operational Research Society Ltd. All rights reserved.