Many organisations have become aware of the limitations of their legacy systems to adapt to new technical requirements. Trends towards e-commerce applications, platform independence, reusability of pre-built components, capacity for reconfiguration and higher reliability have contributed to the need to update current systems. Consequently, legacy systems, typically designed and developed using traditional methods, need to be re-engineered into new component-based systems. The objective of the study is to develop a method to compare traditional and component-based models of systems. Design science is the approach used to build and evaluate the method. The method incorporates and integrates existing methodologies for information systems re-engineering and conceptual model evaluation. A case study illustrating the comparison method revealed that a reengineered component-based conceptual model was capable of representing and enriching all the traditional conceptual model constructs. However, there was a conflict with the use of data flows as these can represent both events and also couplings between processes, data stores, and external agents. Thus, the project derived an additional set of rules to use when generating a component-based model to improve the re-engineering step.