Aim: The aim of the study was to evaluate the usefulness of P300 potential as a diagnostic exponent of central nervous system changes in subjects chronically abusing alcohol and subjects in the period of abstinence and also to find the correlation between the changes of parameters of P300 potential and radiological indicators of brain atrophy in these subjects. Material: The material comprised three groups of men aged 30-55 years. Group I consisted of 30 men meeting the criteria of alcohol dependency syndrome, with diagnosed alcohol-related toxic liver damage Group II consisted of 30 men with alcoholic history, meeting the criteria of alcohol dependency syndrome, with no traits of toxic liver damage, remaining abstinent for at least one year Control group consisted of 30 physically and mentally healthy men, with no alcohol dependency syndrome. Methods: The following were carried out in all the examined: examination of auditory endogenic P300 potential cerebral computed tomography. Results: Between the studied groups the existence of statistically significant differences concerning parameters of P300 and radiologic indices of brain atrophy (F/A, A + B, C, SW) was found; no statistical significance of D/A index was found between the studied groups (p > 0,05). Conclusions: The diagnostic value of endogenic P300 potential as an electrophysiologic exponent of cognitive dysfunction in subjects addicted to alcohol, also in the period of abstinence, has been confirmed.The decrease of P300 amplitude in alcoholics may be acknowledged as a permanent feature of alcohol abuse.In subjects abusing alcohol chronically, also in the period of abstinence, there has been found a correlation between latency of P300 and radiological indicators of brain atrophy: SW (width of sulci on the surface of brain) and C (width of the third ventricle) and between P300 amplitude and SW index.