Post-consumer waste has garnered attention for its potential to promote sustainability, minimize environmental impact, conserve resources, and generate economic opportunities. This study investigated the use of post-industrial waste (PIW) and post-consumer cotton waste (PCW) in denim by turning it into yarn and combining with virgin cotton to study the mechanical and in-service properties. Open-end rotor spinning was used to produce yarns for fabric manufacturing. There were four warp yarns of 98 Tex having yarn compositions i.e., 100% Virgin Cotton, 100% PIW Cotton, PIW: Virgin cotton (70:30), PIW: PCW (70:30) cotton and two weft yarns of 58 Tex having yarn composition 100% Virgin cotton and 100% PIW cotton and a total of four warp-weft yarn combinations were employed to produce the fabric. Resultantly, the fabrics made were having overall composition 100 % virgin cotton, 100% PIW, 50% virgin and 50% PIW, and 80% PIW and 20% PCW. The fiber results show that the strength, uniformity and fiber length reduce from virgin, PIW and PCW, respectively. Open-end rotor spun made with different percentages of PIW and PCW has comparable hairiness and fiber release to virgin cotton. This suggests post-industrial and post-consumer waste yarn could be used to make denim without compromising the quality of fabric. The mechanical testing results of the fabric show a modest decline compared to virgin cotton fabrics. Still, these properties were acceptable for denim manufacturing.