This study collected the basic data required to develop a slim-fit jeans pattern for upper grade elementary school girls. First, a fit evaluation was made by selecting five slim-fit jeans of ready-to-wear brands. Subjects were four girls aged 11-12 with an average body size that evaluated the appearance and motion functionality of five brands of jeans. Five experts also evaluated their appearance. Second, pattern sizes were analyzed and compared with the average size of upper grade elementary school girls by measuring the pattern sizes of five brands jeans. As a result, Brand A received a high score in appearance and motion functionality. Brand E scored high with Brand A in appearance, while Brand E had the lowest score in motion functionality. For most of the five brand jeans, (+) ease was added to include a wide range of body sizes for upper grade elementary school girls, but the hip circumference, thigh circumference, and knee circumference of Brand E jeans were smaller than the average size of girls. The (-) ease was applied to make the figure look slim, which resulted in a high appearance score. However, since Brand E received a low score in the motion functionality, it could be seen that the (-) ease was not suitable for subjects although the material was stretchable. The result of this study will be used to develop a slim-fit jeans pattern suitable for upper grade elementary school girls.