The paper reports the whole aspects of “HICADEC”, abbreviation of Hitachi Zosen's System for Computer Aided Design, Engineering and Production Control, which has been put to actual use in shipbuilding since 1986. The system enables the designers to perform totally integrated CAD/CAM tasks for ship structure, piping, outfitting and electrics interactively with work stations through three dimensionally processed data base. System concept, newly introduced, is to establish useroriented CAD/CAM system being capable to enhance the system architectures flexibly along with the future technology development. So as to realize the above, the system consists of several subsystems, hull, arrangement, piping and electrics, being composed of so-called packaged-type softwares corresponding to individual functions. In addition, data bases are opened for common use between subsystems to communicate data each other.