In design, manufacturing and usage of technical products uncertainty arises according to process properties and results in influence of products properties. In current CAD-systems, where products and product properties are presented, uncertainty is not considered yet. In this paper, we propose a new enhanced concept for the visualization of information about uncertainty in CAD-systems. The presentation of uncertainty is realized on basis of three-dimensional parametric models in a CAD-system and an implemented uncertainty-browser. The uncertainty-browser acts as a graphical user interface to categorize information about uncertainty, the processes and product properties. Beyond that, information about uncertainty will be visualized as annotations referring to chosen properties. Being aware of information about uncertainty during product design, the engineer is able to improve his product. The representation of uncertainty is based on an ontology based information system for supporting the collection and categorization of information about processes, products and uncertainty.