Most manufacturing companies are trying to develop a competitive product by increasing the quality, shortening time to market and reducing the cost of a product. Collaborators related to the development of a new product want to confirm geometric forms and dimensions during the design process, as well as to verify dimensional errors of a product during the fabrication process. Objective of this paper is the development of a collaborative design and dimension verification system on the Internet. STEP files obtained from the design process are used for the design and dimension verification. Functions of the design and dimension verification modules are constructed over the ActiveX control using the visual C⁺⁺ and OpenGL. By using mark up functions over the Internet, collaborators check geometries, interferences, dimensional errors, human factors and form errors, as well as share their design ideas and opinions with XML rapidly and remotely. The usefulness of the developed system is confirmed through case studies.