In recent years, it has become important for a sustainable environment that clothes are biodegradable, and that unused clothing does not pollute the environment by decomposing in nature. Cotton, especially organic cotton, can decompose very quickly in nature. Since organic clothing manufacturing is a new field, unlike conventional products, seam performance and biodegradability to be conducted on these products are essential in creating new data for the textile and clothing sector. This paper presents an experimental study of the seam performance and biodegradability properties of organic clothes for their sustainability. In this study, six groups of fabrics with a plain weave structure were produced to examine the seam performance and biodegradability of clothes made of organic cotton woven fabrics. Each group includes three different samples of the fabric: conventional cotton fabric dyed with reactive dyes, organic cotton fabric dyed with reactive dyes, and organic cotton fabric dyed with natural dye. Therefore 18 samples having different properties were obtained. Fabric breaking strength, seam strength, seam efficiency and biodegradability tests of these fabric samples were determined. Sample women's blouses were sewn from the fabric samples used in the experimental study, and the blouse appearances were visually presented on the mannequin.