Sustainable Supply Chain Management and Closed-Loop Supply Chain Management have developed to established concepts in literature as well as in practice. There is evidence that environmental damages, waste and resource use can be decreased via product returns and the reuse of certain goods. Since the fashion sector and the corresponding supply chains face extreme challenges in achieving sustainable development, this master thesis focuses on a practical example of second life apparel supply chains in Austria. Building on two case studies from the apparel and textile return industry, one commercial company and one social oriented non-profit organization are investigated. The purpose of this study is to outline how second life apparel supply chains are organized in Austria compared to other countries and which challenges and problems occur along the entire supply chain. Findings suggest that each supply chain consists of a collection and product acquisition phase, different remanufacturing activities such as sorting, grading, recycling and packaging and last but not least the secondary markets where used apparel is sold. Out of this and in line with literature, several challenges have been identified such as the decreasing quality of old garments, difficulties in adequate product return management processes, non-profitability of remanufacturing activities, finding secondary markets, increased competition and complex coordination of the different actors along the supply chain.