The effects of environmental conditions on the antibacterial activity of finished single jersey-knitted cotton fabric have been studied. The fabrics were bleached, finished separately with antibacterial chemicals, and subsequently exposed to chemical solutions that simulated use and wear. The resulting antibacterial activities were evaluated against S. aureus and E. coli bacteria using AATCC Test Method 100-1999. Bleaching and antibacterial finishing led to significant reductions in bacterial growth. The leaching (control led-release) antibacterial mechanism was found to be more effective than the non-leaching mechanism on the respectively finished cotton fabrics. The finished bleached fabrics maintained good antibacterial activity against S. aureus even after the fabrics were exposed to urine.