In a manufacturing layout, it is widely agreed that the design of the layout and aisles for material handling needs to be considered simultaneously. This paper presents an integrated method to optimize the manufacturing layout and aisle structure by simulated annealing. In the method, the layout design problem is represented as a slicing floorplan and the slicing lines in the floorplan are used as the aisle structure for the material-handling system. A new representation for a sliced floorplan is provided so that it can be handled by simulated annealing to perform the optimization. The method minimizes the material-handling cost, which is calculated by the aisle distances between delivery stations, while designing the aisle structure at the same time.