For a small engineering company, managing multiple new product development projects can be demanding. The purpose of the research reported in this paper was to develop an extranet design approach for supporting decision making for engineering new product development activities. A one year case study in a small UK engineering company was used as a basis for developing the new product development extranet design approach reported in this paper. The advantages of a new product development lifecycle ontology approach to engineering R&D extranet design included: a mechanism for classifying new product development data, enabling extranet content to be easily structured; a mechanism for establishing ownership of and access to new product development data, enabling more straightforward content management and security; and a mechanism for supporting presentation of content to various types of staff involved in new product development.