When a single tactile stimulus is presented together with two tones, participants often report perceiving two touches. The present study used an oddball paradigm together with event-related brain potential (ERP) recordings to investigate the neural correlates of this multisensory illusion. ERPs were recorded while rare single tactile stimuli accompanied by two tones (1T2A) were presented amongst frequent tactile double stimuli accompanied by two tones (2T2A). Although participants were instructed to ignore the tones and to respond to single tactile stimuli only, they often failed to respond to 1T2A stimuli ("illusionary double touches", 1T2A(i)). ERPs to "illusory double touches" vs. "real double touches" (2T2A) differed 50 ms after the (missing) second touch. This indicates that at an early sensory stage, illusory and real touches are processed differently. On the other hand, although similar stimuli elicited a tactile mismatch response (MMN) between 100 and 200 ms in a unisensory tactile experiment, no MMN was observed for the 1T2A(i) stimuli in the multisensory experiment. “Tactile awareness� was associated with a negativity at 250 ms, which was enhanced in response to correctly identified deviants as compared to physically identical deviants that elicited an illusion. Thus, auditory stimuli seem to alter neural mechanisms associated with automatic tactile deviant-detection.