Enterprise systems (ES) are large, complex highly integrated information systems designed to meet the information needs of the organization. Limited research has been conducted on the use of external expertise in information systems and virtually none as it applies to enterprise systems. This paper addresses the issues associated with the use of external expertise in enterprise systems. It looks at the ES implementation life cycle and identifies where in the implementation process external experts are utilized and what roles they fulfill in the implementation project. The paper concludes with a New Zealand case experience illustrating the use of external experts in a major enterprise systems implementation.