Although there is considerable evidence that visual stimuli are processed in a parallel and capacity-free manner, recent data suggest that letter perception is a limited capacity process in at least some situations. Research on practice effects in perception has been interpreted as indicating that perceptual tasks that initially demand attentional capacity can be performed in an automatic and capacity-free manner after much consistent practice. The present research investigated the effect of practice on the attentional demands of processing a multi-stimulus letter display. The results showed that practice did not eliminate capacity limitations although there was evidence of a decline in the capacity demands of the feature integration stage of perception early in practice. The fact that capacity limitations generally persisted throughout the experiment suggests that there is at least one other source of limited capacity processing in letter perception and that this source is much less affected by practice.