Natural dye extracted from Eucalyptus bark was applied to cotton fabrics by conventional method of dyeing. Alum, Vinegar, Myrobolan, Betel leaves, Copper sulphate (CuSO4), Alum + CuSO4, Vinegar + CuSO4, Myrobalan + CuSO4, and Betel leaves + CuSO4 were the treatments used for mordants. The dyeing was carried out with and without mordants by pre-mordanting method. The colour of each dyed material was investigated in terms of CIELAB (L*, a* and b*) and K/S values by perimer color scan. The colour fastness to washing, rubbing (dry and wet), light and perspiration of aqueous dyed fabrics were tested according to ISO standards. Results showed that cotton dyed fabrics without mordant showed a shade of reddish brown, while other mordants exhibited light to dark brown shades. The colour fastness to washing and perspiration were good except unmordanted fabric which showed moderate to good fastness to washing, whereas colour fastness light and dry rubbing were excellent for all fabrics; wet rubbing was good for all nine fabrics except unmordanted fabric which showed moderate to good fastness.
