Purpose – In recent years, large engineering consultancy firms in the Netherlands have implemented enterprise resource planning (ERP) systems. The purpose of this study is to shed light on the changing role of information technology (IT) in these firms after implementing ERP. Design/methodology/approach – This change is analysed by focusing on the changing strategic role of IT, the level of IT maturity, and the implementation methods and related organisational changes before and after the ERP implementation. Empirical case study research was conducted by analysing ERP implementations in ten large Dutch-based engineering consultancy firms. The implementation of ERP within these firms is expected to be typical of the way large engineering consultancy firms in the Netherlands have dealt with this technology. Findings – The study shows different but consistent fits among the strategic role of IT, the level of IT maturity, and the implementation method in the different stages of the ERP-implementation. Originality/value – In the future, ERP will play a strategic role within engineering consultancy firms if they adopt tools for the inter-organisational standardisation of primary processes in the context of large construction projects. Inter-organisational use of IT tools in engineering consultancy, however, requires a substantial increase of the intra-organisational IT maturity and a strategic orientation. If this occurs then it can be anticipated that ERP will be used as an agent for radical change.