The purpose of this study is to develop the three-dimensional shape measurement system for the casts of edentulous jaws. This system was equipped with a high precision laser displacement meter and a scanning machine controlled by a personalcomputer. The HIP plane was utilized as reference to standardize the shape measurement procedure for residual ridges. The data measured by this system were analyzed with the programs we developed as follows. The crests of ridges and mucobuccal folds were searched automatically. The parameters of morphological factors such as the height and the width of residual ridges and arches were calculated from these anatomical reference points. Four kinds of pictures were prepared for displaying the analysed results. The first and second ones showed 12 serial sagittal and frontal cross-sectional contours for each cast. The third displayed a cross-section with the value of parameters and the last was three-dimensional graphics of the entire cast shape. We could observe and analyze the shape of residual ridges with computer graphics and save these data on floppy disks by this system. It was suggested that this system could be useful to design complete dentures and to estimate the prognosis of denture treatment.