The purpose of this project is to develop a prototype expert system for arc welding process selection.This expert system was developed using the Knowledge Engineering System (KES). Production Rules for the main program and Turbo C language for the subroutines to this system. The two considerations for process selection in the arc welding field know as technical consideration and cost consideration and this program is based on the knowledge of technical consideration. In this program, there are four types of arc welding processes taken into consideration which include shielded metal arc welding, gas tungsten arc welding, gas metal arc welding and submerged arc welding and the program is limited to prismatic welding only. Before proceeding to the development ofthe prototype expert system, an overview of expert system concepts and structure have been discussed. This is followed by the study of the programming language, KES and the various type of arc welding processes. A detail discussion about the elements of process selection based on the technical consideration is also presented. Finally, the discussion of the prototype expert system starts with the system concepts and characteristic, organization of the system, knowledge bases and a sample program run. A significant degree of success has been achieved in the development of the prototype expert system. Modifications have to be made to improve the capabilities of this program.