In order to investigate seam puckering in thin fabrics for summer clothing, this experiment was conducted. Eight different fabrics were sewn with ten different kinds of sewing thread, three different sizes of stitch, and three sewing directions and effects on puckering were examined. The results are as follows: 1. More seam puckering appears on thin fabrics than on thick ones. 2. Less seam puckering appears with the smaller sizes of stitch. 3. Slant direction of sewing gets less seam puckering. 4. Almost no puckering appears with slant direction even after washing.