Organizations are making large investments in package based Enterprise Resource Planning (ERP) systems. While some organizations have achieved business improvement from their ERP systems, many still fail to realize the benefits identified at the project outset. One recommended approach to improve the likelihood of ERP system success and thereby delivery of benefits, is to avoid package customization. However, it appears that implementing a truly 'vanilla' system, although desirable, is rarely achieved. The degree of customization may also be important in influencing the level of benefits realized from ERP systems. A more tailored system may provide a better fit with organizational processes and hence the increased chances of benefits realization. Research that explores the relationship between ERP system customization and benefits realization is lacking. This study helps to fill this gap using an existing benefits management framework and explicitly examining the role of customization in ERP projects. The research method will be exploratory research followed by two in-depth case studies. It is anticipated that investigating the role of customization will significantly advance our understanding of the benefits realization process from ERP system projects.