Historically, gating design relied heavily on the knowledge and experience of the mould designer. A number of automated gating design systems have been developed to overcome this difficulty. While it is important to consider design constraints in real applications, they are not considered in most of the aforementioned automated gating design systems. Moreover, considerable effort and expertise in both CAD and CAE operations are still required in these systems, especially when design constraints are considered. In this investigation, an automated routine is developed to handle design constraints in automated gating synthesis, taking advantages of functionality of both CAD and CAE systems. Standard deviation of filling time is used as the objective function during the gate optimisation process. Design constraints considered so far are no-gate constraints for three-plate moulded part and edge-gate constraints for two-plate moulded part.