We developed a surface modification of electrospun nonwoven nanofiber mat by surface-initiated atom transfer radical polymerization (ATRP) Nanofibers of poly(methyl methacrylate)-co-poly[2-(2-bromoisobutyryloxy)ethyl methacrylate] were prepared by electrospinning to form a nonwoven nanofiber mat containing bromoalkyl groups, which initiated ATRP of 3-[dimethyl(methacryloyloxyethyl)ammonio]propanesulfonate (DMAPS) and 2-(perfluorooctyl)ethyl acrylate (FA-C-8), respectively, without deformation of nanofiber structure. The surface of the obtained electrospun nonwoven nanofiber mat was characterized by XPS, SEM, AFM, and contact angle measurement before and after surface modification.