Collagen and chitosan blends were fabricated into ultrafine fibers to mimic the native extracellular matrix (ECM). So far less mechanical property investigation of electrospun fibers has been reported because of the small dimensions of micro and nanostructures that pose a tremendous challenge for the experimental study of their mechanical properties. In this paper, the electrospun collagen-chitosan complex single fibers and fibrous membrane were collected and their mechanical properties were investigated with a nano tensile testing system and a universal materials tester, respectively. The mechanical properties were found to be dependent on fiber diameter and the ratio of collagen to chitosan in fibers. Fibers with a smaller diameter had higher strength but lower ductility due to the higher draw ratio that was applied during the electrospinning process. For the electrospun single fibers, the fibers demonstrated excellent tensile ductility at chitosan content of 10% and 20% and the highest tensile strength and Young's modulus at chitosan content from 40% to 60%. For the electrospun fibrous membrane, the ultimate tensile strength of the fibrous membrane decreased with the increase of chitosan content in fibers and the trend in the ultimate tensile elongation is similar to that of the single fiber. (C) 2009 Elsevier B.V. All rights reserved.