Wool suits are always preferred due to their warmth retention in cool weather, comfort, and aesthetic features. Seams are very important for the quality of wool suits. The tensile characteristics of seamed fabric change with the change of fabric bias angle. This study aimed to investigate the effects of different seam angles with various stitch densities on the seam strength and the seam breaking extension of wool suit stitches. In this study, seam strength and seam-breaking elongation at different bias angles were investigated for the stitches of trousers and jackets of wool suits. As is known, in the production of trousers and jackets, the seams are applied not only in the direction of the weft and warp but also in the different bias angles at the crotch area and arm hole seams. Six wool fabrics with different structural properties were chosen as experimental samples. Fabrics were cut at 0 degrees, 30 degrees, 45 degrees, 60 degrees, and 90 degrees angles and then sewn with three different stitch densities (3, 4, and 5 stitches/cm ), with lockstitch stitch type for each fabric angle. Therefore, 90 differently seamed fabric samples were prepared. The results indicated that seams prepared with 0 degrees,45 degrees and 90 degrees bias angles give the highest seam strength and that 30 degrees, 45 degrees, and 60 degrees bias angles give the highest seam-breaking elongation values all over the samples. Seams prepared with 30 degrees and 60 degrees bias angles give the lowest seam strength, and 0 degrees and 90 degrees bias angles give the lowest seam-breaking elongation values all over the samples.