Several software component models support composite components, such as Fractal, OpenCOM, Koala, Kobra and SaveCCM. A composite component encapsulates components and provides introspection and configuration mechanisms. Composite components are recognized as a good practice because abstract complex structures and increase reuse. However, there is not a comprehensive study about composite component mechanisms addressing issues like initial composite configuration, mapping of subcomponents services and dependencies through composite component’s interfaces, introspection, component sharing, and composites life cycle. In this work we perform a study about how the Fractal and OpenCOM apply the composite component concept and we propose a new model for composite components. As an experimental study we implemented a new version of the SCS component system with support for composite components, the SCS-Composite. We also present an evaluation of SCS-Composite through the adaptation of a SCS based application.