In this paper an approach for controlling uncertainties in load-carrying systems in virtual product development during the phase of product design will be presented. In design, manufacturing and usage of technical products uncertainties arise according to process properties and they influence products properties. Many of these properties impact each other. These facts lead to deviation of expected property values which are shown for example in the approximation of stress and strength. In cases of load carrying systems misjudgment can lead to disastrous consequences. In this paper an approach for the visualization of information about uncertainty in load-carrying systems in CAD (Computer Aided Design)-systems within the Collaborative Research Center (CRC) 805: “Control of Uncertainty in Load-Carrying Systems in Mechanical Engineering” funded by the DFG (Deutsche Forschungsgemeinschaft) will be described. The representation of the properties’ interdependency is to be expressed by an ontology based system. The visualization of the properties and the information about uncertainty is demonstrated in a CAD-system.