Object Modeling Technique (OMT) by Rumbaugh et al, is a methodology for the analysis and design of object-oriented systems. The primary strength of the OMT methodology is that it allows a complete specification of a system, covering it's static structure, dynamic behaviour and functionality. It models each system from three related but different viewpoints - the functional model specifies what happens, the dynamic model specifies when it happens and the object model describes what it happens to. Each model uses a concise and understandable notation, and thus all three models can be appreciated to a large extent on their own. However, as each of these models represents a different view of the system, they need to be integrated together in order to get the overall picture. Herein lies the crux of the problem as the diversity present in the OMT methodology is also paradoxically it's major weakness. Each model is developed more or less independently, and the interrelationships between the three models are not explicit, resulting in a lack of integration, and subsequent lack of consistency between the object, dynamic and functional models. The purpose of my research is two-fold. Firstly to discover and document the cause of this lack of integration and consistency, namely the apparent weakness of the functional model, caused by the unsuitability of using data flow diagrams to model the functionality of an object-oriented system; and the inadequate inter-model relationships, which are poorly defined and are neither supported by formal steps in the methodology nor a comprehensive illustrated example. The second part of my research involves developing solutions to alleviate this lack of integration and consistency, in the form of a somewhat revised functional model which embraces the object-oriented paradigm; and improved inter-model relationships which extend the OMT methodology, to incorporate guidelines for constructing an integrated analysis model, as well as guidelines for checking the completed model for consistency. The layout of the thesis is as follows. The first chapter introduces the OMT methodology by describing the object, dynamic and functional models as proposed by Rumbaugh. The second chapter documents the two major factors which are responsible for the unsatisfactory level of integration and consistency within OMT, while the third chapter proposes detailed solutions to each of these identified problems in the form of a revised functional model and inter-model relationships. The fourth chapter comprises a case study detailing how to construct the revised functional model, and how to integrate the three OMT models. And finally, the fifth chapter concludes the thesis by discussing the strengths and weaknesses of the revised OMT approach, as well as reviewing current research in OMT, and identifying some areas of potential future research for the methodology.