Tamarind seed coat tannin was extracted and its tannin class was determined. The extracted tannin was employed as a natural mordant alone and in combination with metal mordant namely copper sulphate for cotton, wool and silk fabrics and dyed using natural dyes namely turmeric and pomegranate rind. The colour strength, colour coordinates, wash and light fastness were evaluated and compared for all the three fabrics with and without mordanting. The pre-mordanted fabrics on dyeing gave better colour strength, wash and light fastness than those dyeing obtained without mordanting. The total phenolic content of the extract was calculated and minimum inhibition concentration was 1% against both the Staphylococcus aureus and Escherichia coli bacteria. The mordanted and dyed fabrics resulted in good antibacterial activity up to 20 washes, when natural mordant was used along with 0.5% and 1% copper sulphate mordant and dyed with natural dyes.