Requirements definition, where engineers interact with clients to better know the organization`s activities and understand their needs, is a key process to the success of an information system. As such, requirements defined with clarity and according to the client`s needs are fundamental to the development of effective information systems for the organization. This dissertation proposes a method to help requirements engineers in the task of eliciting requirements. These requirements must be in accordance with the business as to improve the quality of the organization`s information systems. The proposed method integrates process modeling and business ontology. The work assumes that the integration of these perspectives provides a solid source of organization knowledge. Using this knowledge source, requirements engineers are empowered to define requirements that better fits the organization business. The integration of process modeling and business ontology is described in detail and exemplified by a case study.