In this paper, a heuristic for machine cell-part family identification that addresses some important design constraints—machine capacity, safety, technological requirements, upper limit on the size of a cell and number of cells—is presented. First, a model is used to determine the number of each type of machine necessary to process the parts. The heuristic then identifies a machine cell and corresponding part family. Next, it ascertains whether the design constraints listed above are satisfied, one by one. If not, it attempts to modify the original machine cell-part family combination by adding, removing or duplicating particular machines so that the design constraints are satisfied. Constraints of higher priority take precedence over those of lower priority. Similarly, other machine cell-part family combinations are identified. While generating a solution, the heuristic attempts to minimize the intercellular movement of parts as much as possible.