The application of composites has been increasing dramatically in aerospace structures recently, for example, composites have contributed over 50 percent of the structure mass of large transport airplanes. However, the further usage has been restricted because of the high material and manufacturing costs. Hence, it is essential to utilise cost estimation tools for accurate cost estimation in the early design stages, and then efficient decisions and design optimisations could be made to reduce the cost of composite products. A cost modelling system has been developed for aerospace CFRP composites, which can help designers and cost engineers to estimate the manufacturing cost in early development stages. The system consists of several modules: material selection, process planning, cost estimation, cost reporting and a user friendly interface. Moreover, the selection and planning modules are combined with databases, including material and process.