In the present study, the relation of preparatory brain slow potentials (SPs) to postural body sway during sharpshooting performance was examined. SPs from frontal, left-central, and right-central areas were recorded from 6 elite and 6 non-elite sharpshooters during a realistic simulated shooting task. A force platform technique was used in the recording of postural sway. The results showed that body sway, as indexed by sway amplitude and mean velocity, was associated with the concomitant SP changes. That relationship was dependent on the shooter's expertise level, however. The main finding among the elite shooters was that the reduced amplitude of body sway coincided with reduced frontal positivity, whereas in the non-elite shooters, the amplitude of sway and the mean sway velocity in the anteroposterior direction were typically accompanied by the lateralization of central negativity. Those findings offer some new insights for evaluating the functional significance of preparatory brain SPs associated with psychomotor processing in sharpshooting. The results from the present study also have implications for the understanding of the postural strategies employed by shooters of different expertise levels.