Fashion industry is one of the biggest and most successful industries, but also at the same time it contributes the biggest pollution in the world. Discarded clothing and garment factories result in massive garment and textile waste. This keeps happening because of the consumers’ consumptive behaviour and lack of knowledge in repurposing clothes. To solve this problem, customers need to be educated in repurposing clothes and adding value to the product. This way, it can extend fashion products’ life cycle, and decrease the consumption of massive fashion products. This research aims to identify the upcycling design process in fashion and also classify the methods and techniques in repurposing clothes (especially upcycling), such as 1) subtraction which includes cutting, cropping, slashing of fabrics and garments, 2) deconstruction which includes division and reassembling clothes and other textile materials, 3) addition which includes embellishment assembling, patchworking, etc. and 4) refunctioning which is reusing old products for new purpose . This way, not only upcycling methods are more structured and accessible to everyone, also the upcycling methods and techniques can be employed in the design development of old garments to extend the garments' lifecycle.