In order to obtain basic data for designing knitted garments with consideration of the mechanical properties, the influence of fabric weight and tensile properties on the silhouette of knitted one-piece dresses were discussed. The dresse were knitted using three knids of wool yarns in Table 1 under three levels of the stitch dial. The dimensional changes in the wearing length and the local portions on a dressmaker's dummy were discussed. The results obtained are as follows. The length of the dress knitted with fine yarn under low stitch density, became 20% longer than before wearing, suggesting that same design can give different silhouettes in knitted dresses with different tensile properties. Dimensional changes in the upper and protuberant portions of the dress on the body were found to be larger than those in other portions. It was suggested that prediction of such dimensional changes was possible based on the biaxial tensile properties of the strip. In designing knitted dress patterns, it should be taken into account that different tensile properties of knitted fabrics give rise to different dimensional changes in different portions.