As the design of Ro-Ro ships is rather complex and different from the design of conventional ship types, a new computerized design model is desired. In addition, there have been many developments in computing technology. These developments, such as computer graphics, make it possible to develop an advanced model for ship design. Ship design procedures, problems in the design of Ro-Ro ships, and available computing methods have been studied. Two items are identified as necessary for the conceptual design of Ro-Ro ships. One is the checking of the loading conditions, and the other is the handling of internal geometry. A computerized model for the conceptual design of Ro-Ro ships with 2-decks has been developed. It has a graphical presentation module which shows the midship section and deck arrangements of the ship with cargoes. The first international (ISO) standard in computer graphics, GKS, is used for the module.