The time taken in the cooling stage, of a typical injection moulding cycle, is a large factor in the productivity and efficiency of a plastic manufacturing process, and for this reason, must be minimised. In order to do this a cooling system is employed throughout the mould core. This thesis describes the development and implementation of a PC based analysis system that can be used to optimise the size and position of injection mould cooling systems. The software is fully ‘32-Bit’, operating on ‘Windows’ platforms, and uses graphical methods for input and output operations. The two-dimensional geometry of the mould is supplied using AutoCAD 14 and ‘Active-X Automation’. The analysis programs were written using ‘Fortran PowerStation’ and the user interface using ‘Visual Basic’. To employ the optimisation process the ‘Boundary Element Method’ was used to predict the temperature profile throughout the mould. This method is compared to an analytical procedure and the “Finite Element Method”, by analysing a simple benchmark problem. The results of the “Boundary Element Analysis” were extremely accurate and in close agreement with the analytical solutions. This thesis presents the method by which the temperature profile, throughout an injection mould, can be predicted, and applies this method to a particular example. Also presented are the experimental results of a test mould that was manufactured to produce simple square plastic parts. The results of the numerical analysis agreed with experimental results to within 6%.