The effect of low dosage plasma ion implantation on hydrogen embrittlement was studied for an HSLA steel using notched tensile samples. The plasma treatment caused an enhancement in the linear strain to failure under embrittling conditions. This was however not reflected in the fracture surfaces of the treated samples which had similar fractographic features as those of untreated samples. The plasma treatment delayed the process of embrittlement without causing any alteration in the basic mechanism of embrittlement. This was due to introduction of residual compressive stresses as well as reduction in the hydrogen permeation flux. Implantation in pure nitrogen seemed most beneficial while implantation in pure argon caused very little improvement. (C) 2003 Kluwer Academic Publishers.