Silver nanoparticles find wide use in household and industrial products, including textiles, for their antimicrobial efficacy. To impart the washing durability, the nanoparticles are typically coated onto textiles with some binders. However, currently available surface-treated commercial and laboratory-prepared textile products have shown significant leach of silver nanoparticles into laundry water. This study showed that the in situ internal synthesis of silver nanoparticles within cotton fiber is an effective and reliable way to improve washing durability.