The main objective of extracting natural dyes from natural sources is to avoid the environmental pollution. The flower of Tagetes erecta is used for the extraction of dye using alkaline extraction method. There are four different mordants (CuSo4, FeSo4, NaCl, K2Cr2O7) are used in cotton and polyester fabric by simultaneous mordanting method. The dye fixation is carried out at room temperature and also at 100°C. The result revealed that, different shades of yellow, brown and green were obtained from the dye when subjected to mordant. The dye at 100°C showed dark colours and excellent fastness properties when compared to dye fixed at room temperature. The dye extract of Tagetes erecta had a great antimicrobial activity against pathogenic strains of bacteria and fungi and the FT-IR was carried out to identify compounds.