Chitosan is a natural polymer with both antimicrobial activity and nanofiber-forming capability. The electrospinning technique allows the production of chitosan nanofibers but still faces several problems such as the small number of suitable solvents for the process and the large number of factors affecting quality and production of the nanofibers, among others. The antimicrobial properties of chitosan nanofibers have been little studied; therefore, the most probable mechanism of action and the effect of the conformation or arrangement of the molecules in the nanofibers remain unknown. The presence of residual solvent in the materials is one factor that has complicated the assessment of the antimicrobial activity of chitosan nanofibers. The research in this area will be very important for the future of these materials. (C) 2011 Society of Chemical Industry