Implementing an Enterprise Resource Planning (ERP) system project is a difficult and high cost proposition as it places tremendous demands on organization's time and resources. The ERP implementation literature contains many case studies of organizations that have implemented ERP systems successfully. However, many organizations do not achieve success in their ERP implementation projects. Much has been written about implementation and the critical success factors for ERP implementation projects. But there very few studies have scientifically developed and tested constructs that represent critical success factors of ERP implementation projects. Based on a survey of 53 organizations in Australia, the results suggest that a 65 item instrument that measures seven dimensions of ERP implementation is well validated. It is argued that model proposed in the paper is valuable to researchers and practitioners interested in implementing Enterprise Resource Planning systems.