In order to investigate the effect of atmospheric pressure plasmas on adhesion between aramid bers and epoxy, aramid bers were treated with atmospheric pressure helium/ air for 15, 30 and 60 s on a capacitively-coupleddevice at a frequency of 5.0 kHz and He outlet pressure of 3.43 kPa. SEM analysis at 10 000£ magni cation showed no signi cant surface morphological change resulted from the plasma treatments. XPS analysis showed a decrease in carbon content and an increase in oxygen content. Deconvolution analysis of C1s, N1s and O1s peaks showed an increase in surface hydroxyl groups that can interact with epoxy resin. The microbond test showed that the plasma treatment for 60 s increased interfacial shear strength by 109% over that of the control (untreated). The atmospheric pressure plasma increased single ber tensile strength by 16-26%.