Studies using young, non-impaired adults have shown that by directing attention to the outcome of movements (external focus) rather than directing attention to the movements involved in a specific skill (internal focus), motor skill acquisition is enhanced. The purpose of this study was to investigate the generalisability of these attentional focus findings to balance in subjects with Parkinson's disease.Experimental, repeated measures design.Physiotherapy research facility.Twenty-two subjects diagnosed with idiopathic Parkinson's disease.Subjects were tested under three attentional focus conditions; no instruction, internal focus and external focus.Balance equilibrium scores from three computerised dynamic posturography conditions.A significant condition x attentional focus interaction was found (F [4, 84]=2.86, P<0.05), indicating increased sway with internal focus relative to no focus instructions (control) under the eyes-open condition. More importantly, when only subjects with a history of falls were considered, there was a significant interaction between condition and attentional focus (F [4, 36]=4.40, P<0.01). Post hoc tests revealed that the external focus instructions resulted in less sway than both internal focus and no attentional focus instructions under sway-referenced conditions.These findings support previous research studies on attentional focus. In particular, it was demonstrated that the balance of subjects with Parkinson's disease and a fall history can be enhanced by instructing subjects to adopt an external focus.