The surface morphology and molecular arrangement of a Kevlar(R) aramid fibre (coded Fibre A, from E. I. DuPont de Nemours and Co.) were studied by atomic force microscopy (AFM). Pleats parallel to the fibre axis have been observed. At nanometre scale, the polymer chains display several different arrangements from the reported crystalline structures for the bulk polymer especially in the polymer chain direction. The benzene rings at the surface seem to have a co-planar like rotation instead of an opposite one as proposed for bulk crystalline structure according to X-ray diffraction results. The factors inducing the less perfect surface crystalline structure are discussed.