Business process definitions might serve variety of purposes. Two common uses of process models are business process management and software requirements analysis. Although commonalities exist, different models are established for these goals. Establishment of different models not only requires larger amount of effort but also results in inter-model inconsistencies and creates overheads for keeping the models integrated. This paper describes a case study to establish a unified modeling approach for overcoming these difficulties. The case study was performed in a large scale governmental organization. As part of the case study, process models were developed and requirements definitions were generated from process models. The outcomes of the case study were validated by the organization who utilized them in generating quality manuals as well as acquiring software artifacts. The results show that, business process models can be used for software requirements analysis, while the total effort for business process modeling and software requirements analysis is significantly decreased.