OBJECTIVES OF THE STUDY: The objectives of the conducted research were to determine the sources and most common sources of caffeine consumption in the population of students at the University of Osijek, to determine the reasons for caffeine consumption, to determine the frequency and type of side effects of withdrawal syndrome due to caffeine intake, and to determine the level of knowledge about the influence of caffeine with regard to the field of study and the influence of knowledge about the effect of caffeine on the frequency of caffeine consumption. STRUCTURE OF THE STUDY: Cross-sectional research. SUBJECTS AND METHODS: The research included 1197 respondents (students) of both sexes from all components of the Josip Juraj Strossmayer University of Osijek. The research was conducted using an anonymous questionnaire consisting of 29 questions. RESULTS: The conducted research determined that the most common source of caffeine consumption is instant coffee, followed by teas (black and green) and ground coffee, while other sources of caffeine intake were insignificant. It was found that subjects who smoke cigarettes consume significantly more caffeine and caffeine consumption increases more as they smoke cigarettes more often. Respondents suffering from one or more chronic diseases consume more caffeine. Also part-time students consume significantly more caffeine than full-time students. The frequency and impact of side effects, such as withdrawal syndrome symptoms or psycho – physical side effects that could be attributed to the effects of caffeine are minimal. CONCLUSION: Subjects consume more than 400 mg / day of caffeine, which is more than the maximum estimated safe daily dose. Despite this, they have rarely experienced side effects of caffeine, and most of the subjects have never experienced side effects like difficulties in social, work, or academic functioning due to caffeine intake. The most common source of caffeine is instant coffee, followed by ground coffee and teas. A smaller proportion of subjects, 315 (26, 30 %) of them learned about the caffeine effects during their academic education.