In the analysis of information systems, data and process have been loosely coupled. Object-oriented approaches have been proposed to integrate these two aspects tightly. Object-oriented approaches, however, are based on a radical paradigm and thus, it is difficult to move from conventional structured analysis to Object-oriented approach. To alleviate these difficulties, this thesis presents a methodology to systematically transform structured analysis outputs to an Object-oriented model. A real world case is illustrated with detailed design guidelines.