This paper describes the assessment of the antimicrobial effect of leathers employed for footwear production, which were obtained by different tanning techniques and treated with silver nanoparticles emulsions synthesised from different reducing agents (sodium borohydride, gelatine/glucose and Aloe vera extract), as well as the assessment of the silica nancomposites obtained from said nanoparticles. After the characterisation of silver nanoparticles and nanocomposites, the emulsions were applied onto different leather samples. Scanning Electron Microscopy was used to verify that silver nanoparticles were deposited on the collagen fibres surface and inside the collagen matrix of leather. The antibacterial effect of different silver nanoparticles and silver nanocomposites was assessed on gram positive and gram negative bacterial strains in agar diffusion assays and turbidimetric tests. The results obtained proved a powerful antibacterial effect on all bacterial strains tested of both silver nanoparticles and silica nanocomposites. This allows us to consider the incorporation of these nanocomposites into leather as an alternative to other commercially available products in order to obtain leather with antimicrobial properties that confer better functionality and added value.