The application of computei aided design and computer aided manufacturing (CAD/CAM) technique to forming is gaining populanty as the lesulting productivity improvements are becoming more and moie appatent. Most users are using CAD/CAM and finite element packages as stand alone packages, where the integiation among these packages in most cases is difficult due to the diffeiences in the layout format of each one. Finite element packages usually have then own pie- and post piocessors, however it is unlikely to include the facilities available in a CAD system such as zooming, pan, layer. This thesis describes a PC-based intei active CAD system foi closed die forging design. This system includes the facilities foi drawing the die geometry, simulation of the deformation process and die analysis undei forming condition. First of all, a commeicial CAD system has been customized to accommodate the empirical guidelines foi closed die foiging design Then a Finite Element program FE has been developed based on the ngid plastic/viscoplastic formulation to simulate the metal flow. A mesh geneiation piogiam has been developed as pait of this system. The CAD system has been used as pie- and post piocessoi foi the mesh generation and the FE programs. To overcome the pioblems encounteied in forming piocesses, such as large deformation and displacements which cause ceitain computational pioblems, a lezoning algorithm has been developed. An elastic/plastic FE piogiam has been used foi die analysis, the FE simulation results of the forming process are used to find out whethei the analyzed die would sustain the forging load or not. This metal flow simulation and die design piocess has been applied to two closed die forging examples, one in plane-stiam condition and the othei in axisymmetric condition. The results were encomaging and in close agieement with the experiments.