The prime objective of this thesis is to research and develop a new system of project budgeting, monitoring and forecasting to meet the needs of the Construction Industry. It is intended that this work will facilitate the means for more efficient control of projects from inception to final completion, utilising where possible the latest developments in computer technology. The initial stage of the work involves an investigation and appraisal of existing methods of formulating project budgets. In particular attention is paid to previous work in the development of mathematical 's' curve models, together with their limitations in use and application. Potential for future development is also identified. The thesis then focuses on the evolution of an improved modelling philosophy for project budgets and forecasts which overcomes previously known problems. In parallel with this work is the development of a computerised system intended to enable the testing of the model against live project data. The model finally selected is then tested against the extensive research work previously undertaken by the DHSS and the data collected from sixteen construction projects. To facilitate the development of a suitable control system to act as a vehicle for the application of the principles developed, a contextual survey is included. This survey is intended to provide an update of previous survey work undertaken by the author in 1977 and to further investigate factors orientated specifically to the objectives of the thesis. The research then concentrates on the development of an integrated set of sub-systems which contribute to the budgeting, monitoring and prediction of project expenditure. These systems are developed in accordance with the need to establish the financial status of projects both before, during and after they are completed. The overall system is based on the latest computer technology available and is designed to be flexible in its application. Tests documented in the text prove that the system operates both in principle and in practice. A further extension of the research is the use of the various project data bases to provide information for a corporate control system which has been developed in principle. This thesis provides a significant step forward in computerised project budgeting and control utilisng 's' curve philosophy and provides a basis for further development. Potential exists for future development of the prediction and corporate control systems, together with software developments to improve general application over a wide range of industries and disciplines where project work is undertaken.