This paper assesses the changes in colour differences (Delta E-ab*), lightness (L*), chroma (C*) and colour strength (K/S) values of polyester automotive seat cover fabrics after five durations of exposure to ultraviolet (UV) light using different fabric constructional parameters. At each level, the UV-exposed fabric was compared with the fabric in its original state and the colour properties were determined. The * ab.E colour difference values of all of the fabrics increased as the fabric cover factors decreased. The chroma and colour strength values decreased and the lightness values increased as the exposure times increased. Compact fabric structures with high cover factor values that were woven from high-count yarns with a high number of yarn crossings were found to be more resistant to UV exposure. To produce fabrics that are colourfast in UV light, the constructional parameters of the fabrics must be carefully chosen in terms of yarn and fabric constructional properties.