This paper presents an ontology modeling and engineering approach to semantic description and integration of product development processes. Using OWL and OWL-S, the proposed method formalizes the underlying semantic representations of the product development process in domain object ontologies and the generic problem solving structures in domain task ontologies. Both the domain object and task ontologies are incorporated in the OWL-S based application service ontologies to facilitate the semantic process description and semantic service discovery, composition in the integration of product development processes. The approach has been applied to the development of ontological models for the consumer product development process in a pilot project of a national research program in Singapore namely the Integrated Manufacturing and Service Systems (IMSS).