Shared service centers are a common approach for organizing IT service provisioning. However, current research reveals little that both consultants and scientists maintain a fragmented understanding of the basic characteristics of SSCs and their different variations. From SSCs with free access to external markets, to SSCs with restricted access or no access to external markets, many facets of the SSC require further clarification. Other criteria such as legal form, organizational structure, and accounting approach vary across different departments. The general elements describing SSCs are extracted from literature and show a common understanding. Based on material gathered during focus groups and extensive case studies in 7 SSCs from Europe and North America, our study extracts typical SSC characteristics, as well as their distinctive attributes, and designs a classification grid. This framework is used to classify three typical profiles that have been identified.