This study focus on the re-engineering of Tube-Feeding-Diet (TFD) and Tray Meal Diet (TMD) operation processes in the Nutrition Department of a Medical Center. In the concerned case, the Nutrition Department has to serve 541, 000 person-times TFD and/or TMD per year. Such intensive requirement jeopardizes the quality of the operation processes in the Nutrition Department. After conducting business process analysis and re-engineering, there are six major problems in TFD service process: (1) The inappropriate design of the existing tables and sheets leads to inefficiency in the operation processes. (2) Frequent mistakes occur because of the improper operations in the processes. (3) The manager is not able to obtain a precise measure of the discarding cost. (4) Without the assistance of an effective information system, it results in both increasing cost from intensive manual operations and good possibility of making mistakes. (5) The manager suffers from the problem of no complete and accurate information of the amount consumed. (6) The manager is not able to fetch necessary managerial information from the statistical sheets. On the other hand, there are four major problems in TMD service process: (1) Inappropriate design of the existing catering card operating system leads to inconvenience in the operation processes. (2) Inefficiency in the operations occurs because of the unequally working loading assigned to the staffs in food service. (3) Low subscribing rate of Tray Meal and Liquid Diet results from lacking of promotion and market segmentation. (4) It is difficult to increase the revenue of partial catering because of the restriction of existing subscribing system. In order to solve the problems in TFD service process, we propose a eight-step procedure as follows. (1) Design new tables and sheets to replace the inappropriate ones in the TFD service operation processes. (2) Modify the design of the diet-change order sheet and change the operation processes. (3) Replace the existing diet-sheet with a new self-sticking label accompanying with a new design that shows clear and necessary information. (4) Introduce new catering tables and sheets to replace the existing ones. (5) A discarding procedure is proposed for the TFD service operation processes. (6) Modify the receiving process of commercial packaged TFD in the second medical service building. (7) Propose an inventory checking mechanism for the two secondary storage units in the TFD kitchen and the Second Medical Service Building. (8) Establish a new web-based information system to assist the Nutrition Department in the TFD service operation processes. On the other hand, we propose five action items to solve the problems in the TMD service processes: (1) Design a new catering card operating system. (2) Modify working loading assignment to the staffs in food service equally by using the assembly line balancing method. (3) Initiate perspective promotions to increase the meal-subscribing rate. (4) Modify the existing subscribing system to explore new sources of clients so as to increase the total revenue. (5) Establish a new web-based information system for the subscription of TMD in the Nutrition Department. Following cautious assessment, the Nutrition Department not only is able to effectively solve the problems using the eight action items in the TFD service process and five action items in the TMD service process, but also would secure a cost-saving of $NTD 221, 000 each month for the case hospital.