Individual characteristics of dorsal median curve and silhouette curve of 120 young Japanese women were investigated for the purpose of obtaining basic information for improving the fit of ready-to-wear clothes. Each of the curves was constructed with 10 mm pitched three-dimensional data measured by grating system for profiling (GRASP). It was confirmed that the shape of two curves could be effectively approximated by a set of three arcs and three straight lines for 114 of the 120 women and expressed by 27 parameters for numerical analysis. The median curve and silhouette curve correlated at the parameters for the shape of the upper back area, the concavity of lumbar area and the protrusion of the gluteal area, and the inclination of the upper torso. A principal component analysis done using 12 out of 27 parameters extracted five components for the silhouette curve. The first three principal components were interpreted as the concavity of the lumbar part with the protrusion of the gluteal area, the inclination of the upper torso and the shape of the upper back area, respectively. The dorsal characteristics described by these components will be contrasted with the characteristics of surface developments and apparel pattern in the authors' succeeding study.