A novel algorithm methodology is proposed for cellular manufacturing (CM). This model involves a four-step heuristic algorithm for overcoming the so-called improper machine assignment problem that is commonly encountered in CM. The development of an expert support system for the design of CM is outlined. The proposed expert support system has the flexibility for users to consider CM problems by including a series of practical constraints, such as maximum capacity for machine cells and part families; technological constraints for machines that must (or must not) be grouped together; and the total number of desired machine cells in a final CM solution. An example of the application of the proposed expert support system is presented.