The aim of this study was to determine the prevalence of addictive substance use among students during one-year period, to evaluate the present situation, and to substantiate the necessity of prevention. MATERIAL AND METHODS. The participants of the study were students of the Lithuanian University of Agriculture: 1475 students were inquired in 2005 and 1575 in 2006. The study was performed by applying a questionnaire consisting of 26 standard questions for the evaluation of respondents' health and health-related behavior. The obtained results showed the stability of addictive substance usage among students during one-year period: on the average, 33.6% of males and 20.4% of females were daily smokers. No changes were found in the number of nonsmokers, but the number of students who quit smoking was increased. There were no changes in the pattern of ethanol use during one-year period: the highest percentage of male students used alcoholic beverages once or several times per week (38.5%) and several times per month (39.5%). The highest percentage of female students used ethanol several times per month (55.9%). Ethanol and tobacco consumption per day was high, and there were no changes during one year. The rates of drug use were 35.9% among male students, and 17.7% among female. The amount of psychoactive substances used by students (ethanol per one evening and tobacco per one day) did not change and remained dangerously high. Male students consumed 400 mL of vodka, 280 mL of other strong alcoholic beverages, and 2 liters of beer per one evening, while the mean consumption of wine decreased from 383 mL to 308 mL. The respective findings for female students were as follows: 200 mL of vodka, 150 mL of other strong alcoholic beverages, 300 mL of wine, and 750 mL of beer. Male students smoked 11 and females 7 cigarettes per day, on the average. CONCLUSIONS. It seems that the stability of addictive substance use among students demonstrates that high risk of chronic diseases is related to the balance between social supply of these substances, and prevention of their distribution and usage.