The modernisation of legacy information systems is a problematic and risky process that many organisations 1 will undertake at some stage during their lifetime. When modernising a legacy information system a number of different approaches can be used, ranging from a simple ‘updating’ of the existing system to its wholesale replacement. Little appears to have been written about the problems and risks that relate specifically to these different legacy information system modernisation approaches. Understanding these risks would seem important for project managers when managing modernisation projects and also for decision makers when deciding which approach is most appropriate for a particular project. This paper outlines the initial stages of a research project that to seeks identify, understand and assess the risks involved in both the modernisation process itself and the ongoing use of the modernised system across these various types of legacy system modernisation.