The objective of the research is to identify the main factors that cause expedited and delayed jobs inThai plastic industry from the view points of customers, suppliers, and manufacturers. A realindustrial survey was performed by mailing questionnaires and conducting direct interviews withproduction managers of plastic part manufacturers. The result indicates that many factors can causeexpedited jobs including consumer, competitiveness, and engineering change. The factors that causedelayed jobs include limited storage area, capital shortage, and limited capacity of manufacturingprocess. Consequently, plastic manufacturers have to adapt the production plan to such changes, setnew due dates, and higher or over utilization of machines and workers. This also results in cash flowshortage in the situation of delayed jobs. The research also highlights the linkage between dispatchingrules that can be employed to manage expedited and delayed jobs. For examples, FASFS, EDD,OPNDD, MST, S/OPN, TWORK, LWKR, WINQ, NINQ, MOD, SLACK, and SLACK/TP can beused to alleviate the problem of due date tightness; COVERT can be used to manage the tardinesscost; and MOD and COVERT can be employed to satisfy average lateness.