Electrospinning is a highly versatile technique that allows producing fibers with diameters down to a few nanometers not only from polymers but also from metals, metal oxides, or ceramics. Fiber formation in electrospinning differs strongly from other fiber producing methods such as extrusion in that it is basically governed by self-assembly processes induced by specific electrostatic interactions following the Earnshaw theorem of electrostatics. This allows the production of nanofibers with very peculiar shapes. Here, we report the one step fabrication of barbed nanofibers due to a particular choice of the spinning conditions. Such barbed fibers allow, among others, to control the total porosity of nanofiber nonwovens and to reduce the tendency of linear nano-objects towards aggregation. POLYM. ENG. SCI., 49:148-153, 2009. (C) 2008 Society of Plastics Engineers