Antibacterial silver nanocomposite cotton fabrics were generated by in situ method using Senna auriculata (SA) leaf broth as reductant. Silver nanoparticles (AgNPs) synthesized on cotton fabrics (nanocomposite cellulose fabrics [NCCFs]) were analyzed by different spectral characteristics like FTIR, SEM correlated with EDX and XRD. The SEM analysis revealed that the generated AgNPs on NCCFs were spherical in shape with a mean size of 100 nm. The XRD studies showed that the biosynthesized NCCFs are exhibiting FCC crystalline lattice structure. The FTIR spectra indicated that the hydroxyl functional group in leaf extract is responsible for bioreduction of silver ions into metallic silver. The TG-DTG and DSC analysis showed higher thermal stability and the deterioration in stages. The biogenerated AgNPs in NCCFs exhibited good antibacterial activity against Gram-positive and Gram-negative pathogenic bacteria. The NCCFs also exhibited good mechanical strength. The NCCFs with bio generated AgNPs can be considered for medical and packing applications.