Modelling is one of the most important activities in process engineering since it provides insight into the behaviour of the system being studied. Modelling is also a complex activity as the formulation of appropriate and consistent models requires help from experts and often results in a knowledge-intensive, time consuming and error-prone task. A knowledge-based modelling support system, KBMoSS, has been developed to foster the exploration of the model space, maintain the model’s evolution, enhance the engineer’s understanding of the model, and improve cooperation between modellers. Mathematical models can also be automatically generated within this system. The model generation is based on the modelling approach developed by Vazquez-Roman (1992). Users can either accept the generated model, modify it, or write their own models from scratch. The user interface was designed to allow the description, examination and manipulation of a chemical process with reference to its modelling aspects. It allows flexible navigation through the various parts of the modelling structure and was implemented using the object-oriented paradigm.