Process modelling can be used to provide a comprehensive understanding of business activities and functions and thence a base for detailed process analysis. Business process improvement refers to a family of approaches which aim to help an organisation adjust its processes to fit a dynamic or complex business environment, particularly so as to take advantage of rapid advances in information technologies. However, most business process improvement methodologies do not make significant use of process modelling to guide the evaluation and improvement of business processes. The current research uses process modelling techniques in a systematic and generalisable manner to gain deeper understanding of processes in a particular complex case. By analysis and further probing of the process models, it then seeks to develop a practical methodology for business improvement which will be applicable not only in the case in question but also more broadly. The case explored in detail in this work is the process of Cancer Care and Registration (CCR) in Jordan. This is introduced after a discussion of business processes in general, business processes in healthcare, and methods of business process modelling. There is some comparative treatment of CCR processes in the UK. The main method used for modelling existing processes in the Jordanian CCR case is Role Activity Diagramming (RAD). Models for six major sub-processes were prepared. The models thus produced were validated in discussion with participants. They were then subjected to an extensive analysis, with the objective of discovering whether the processes might be improved. One form of analysis examined the structural properties of the models, to discover for instance how closely coupled different roles were. A second, model-led, form of analysis methodically queried, through interview or questionnaire, each activity or interaction in the models, to see how well it was working, in its particular context, in terms of general criteria such as efficiency or reliability. Thirdly, the notion of non-functional requirements (NFRs), borrowed from software engineering, was used to derive detailed NFRs from high-level business objectives, as a basis for a systematic examination of broad quality levels achieved in existing processes. These complementary analyses, supported by further validation with - I - participants, then provided the base for a remodelling of the processes with the goal of business improvement. The redesign suggestions included indications of where information technology might be introduced or strengthened with beneficial effect. The methods of detailed modelling, systematic analysis, and redesign for business improvement are, while thoroughly applied to the case under investigation, sufficiently abstract to be proposed as a general methodology for the design of business process improvements. The key features of the methodology are that it is grounded in process modelling and brings together functional, non-functional and structural process analyses.