ERP-developers suggest that the business processes they have implemented in their software are the best practices available. This argument is used to convince new ERP-users they best organize their business processes according to the ERP-system, because only then will they fully reap the benefits of ERP. Although often used, the term ‘best practice’ is never defined in relation to ERP-software. The predecessor of ERP, MRP, has also been hailed as a best practice that should be implemented as programmed and would then be profitable. This turned out to be deception for many companies. This paper explores what the ERP-developers, -consultants, and -users, participating in ERP-implementations, believe ‘best practice’ in ERP-software stands for.