We have been studying association between distorted perception and visual event-related potentials, which appear in response to the Poggendorff figure's presentation in Jastrow modification. It was shown that the amplitude sign is determined by the presence or absence of subjective distortion at the earliest and the latest phase of Poggendorff figure's perception. The amplitude of the wave P150 was bigger at the distorted perception, and the amplitude of the waves N200 and P300 was smaller than during perception without distortion. It is suggested that both ascending nervous processes and cognitive processes of analysis are involved into the emergence of the Poggendorff illusion.