In this research work, the antibacterial activity of mordant treated cotton fabrics and also dye ability of them after mordant treatment was investigated. Copper chloride, nickel nitrate and silver nitrate were used as mordant. Very good antibacterial activity for mordant treated fabrics were acheived. The Scanning Electron Microscope (SEM) was used for morphological study. The fabric samples were incubated in mordant solution, then were dyed using Acid, Basic and direct dyes as a synthetic dyestuffs and with natural dyes such as madder and Indigo. The effect of mordant procedure on dye ability was investigated. In this research work, type of dye and metal mordant effect were studied. Various colors have been achieved by using different mordants. The results showed that, the effect of mordant treatment temperature on dye ability is not significant but the changes of mordant type causes changes in hue, great deal and purity of colors. Color intensities of the dyed fabrics were measured by using a UV VIS-NIR Reflective Spectrophotometer, over the range of 200-800 nm. The results showed that, by using different mordant before dying, the relative color strength (K/S values) of the dyed fabrics have been increased and it has shown that, more amount of dye can be absorbed. This effect is more significant in case of using basic dyestuffs. Also the shade achieved after mordant treatment is more brilliant as compare to untreated dyed fabrics. The results are discussed in full paper.