The purpose of this work was to examine whether fast and slow musical tempi have different effects on selective attention evaluated through ERPs and task performance. A high demanding visual selective attention task was performed by the subjects: without music (BL) and with Bach's music in slow (ST) and fast tempi (FT). Difference waves were obtained substracting non-target from target. FT caused a reduction in reaction time and N2d and P3d latencies and in P3d amplitude. N2d latency was longer in ST than BL and FT. Music played in FT induced a faster stimuli evaluation and response than ST.