This study compares alternative shop loading procedures for cellular and functional layouts in a variety of operating environments. Factors investigated here include: (1) the extent to which the parts in a family follow a unidirectional flow; (2) shop congestion level; (3) the magnitude of delays in moving batches between departments; and (4) whether the shop was labour constrained. Computer simulation was used to compare the combinations of shop layout and loading procedure on the basis of time in system. Important managerial implications are presented for selecting a layout and loading procedure given the operating environment.