This project investigates the colorfastness properties of terylene and cotton wool fabrics dyed with roselle (Hibiscus sabdariffa L.) dye, focusing on the effects of mordanting. The study aims to determine how mordanting influences the resistance of these fabrics to washing, light exposure, and rubbing, thereby assessing their practical applicability and durability. The present study used four sets of fabric samples: mordanted terylene, unmordanted terylene, mordanted cotton wool, and unmordanted cotton wool. Standard tests for washing, light, and rubbing fastness were conducted on these samples. The results indicate that mordanting significantly enhances the fastness properties of both terylene and cotton wool fabrics dyed with roselle dye. Mordanted terylene and cotton wool showed superior resistance to color fading and loss compared to their unmordanted counterparts, with marked improvements in washing, light, and rubbing fastness. These findings underscore the importance of mordanting in the dyeing process with natural dyes, ensuring longer-lasting results. Furthermore, the environmental impact of using natural dyes is assessed, considering factors such as biodegradability and the absence of harmful chemicals typically found in synthetic dyes. The results indicate that natural dyes not only offer a sustainable alternative but also exhibit unique aesthetic qualities that can enhance the appeal of dyed products. From the obtained grades for color change and color staining, it can be concluded that the selected mordant, ferrous sulfurat