Lean Machine Tool is the one which meets all customer’s requirements, just enough without being equipped with any unnecessary features or accessories. In acquiring a new machine tool it is neither easy nor straightforward to decide if a given accessory is desirable or not. Addition of any accessory would affect product cost, performance, reliability, and often in conflicting ways. Decision to select an accessory for a given manufacturing situation, requires large information from manufacturer and end user, apart from engineering judgment and prior experience. The present work is an attempt to develop a methodology for making such decisions and to automate the same in the form of an expert system with inputs from both users and manufacturers of accessories. Based on the proposed methodology, a case study is presented to decide an accessory namely automatic loader/unloader for a given machining application.