The methodology presented here is currently being used in the design of Standard Automated Financial System (STAFS), which is a large scale business system for use by the 14 Naval Laboratories across the nation. The system will be operational in 1987-1988 time-frame. The methodology presented is suitable for all transaction oriented systems. It enforces documentation of design at all levels of system development process allowing managers and users a high visibility into the design. It highlights the human engineering aspects of system design and utilizes thread definition, data designer, and structured design techniques. The methodology requires the use of system verification diagrams which specify the user requirements. The design produces an integrated database with security mechanisms to restrict unauthorized users from accessing data they are not authorized to use. The threads also serve as a useful tool for system testing.