Since the introduction of the concept 'world-class manufacturing (WCM)', world-class manufacturing systems (WCMSs) have attracted the attention of industries all over the world. This is evident from the fact that, in recent years, quite a few industries claim they are of 'world class' and many other industries have embarked on their journey to attain 'world-class' status. The perceptible impact of WCMSs lies in attaining the far-reaching world-class standards, but there is a general challenge offered by WCM to the field of engineering economics, when it is necessary to justify adopting or implementing such new philosophies or systems. Typically, the traditional approaches do not account for the significant intangible benefits offered by systems such as WCM. The present work describes the development of a knowledge-based system for justification of WCMSs, to overcome the above-mentioned deficiency. © IMechE 2006.