Acquisition of software intensive systems demands significant work on requirements prior to establishing the contract. The acquirer needs to understand the domain, needs, and constraints of the project clearly in order to make realistic size and effort estimates, and to have a solid foundation for defining contract requirements. In this study, an approach for requirements elicitation based on business processes is investigated. The approach proposes determination of requirements of a software intensive system to be acquired, according to the business objectives and base lining business processes. This study presents the implementation of the approach in a large innovative military application within the boundary of a project for Request for Proposal (RFP) preparation.