Lateral interference of nearby irrelevant flankers may be reduced when attention is already focused at a relevant position. This hypothesis was tested in three experiments with multi-element arrays consisting of one target and several neutral flankers with reaction time (RT) and proportion of errors (PE) as dependent variables. The arrays were preceded by peripheral cues that varied in size to induce different levels of focused attention. In a first experiment, the eccentricity effect was shown to be affected by attention, but no support was found for a reduction of lateral interference in the case of focused attention. However, these results may be due to an attentional bias for central elements. Two additional experiments were performed in which target-flanker distance was manipulated. RTs and PEs showed that the effect of target-flanker distance was smaller when the precise target position was indicated by a peripheral precue. Thus, focused attention seems to reduce the effect of lateral interference. These results can be explained most easily by a model in which attention already affects early perceptual processing.