Abstract Introduction. Increasing interest in dietary supplements designed for athletes is accompanied by an increase in the number of commercial vendors offering a broad range of dietary supplements. It is also followed by phenomenon of wide availability and as a consequence universality of application of this group of preparations. The goal of this research project was to assess the use of dietary supplements by players of selected sports with consideration given to sex, age, education, level of physical activity and training experience. Material and methods . The study was conducted using the diagnostic survey method with the aid of a survey written by the authors themselves. The study population consisted of 216 athletes (100 powerlifters and 116 volleyball players) ages 16÷30.... Statistical analysis of empirical material was conducted on the χ2 basis of an test (p≤0.05 or higher). Results . A clear majority of subjects claimed to be convinced that diet and dietary supplementation exerted an important influence on their athletic performance. Despite giving their own diet a favorable assessment, more than 95% of respondents reported having difficulty following the diet, while simultaneously reporting the causes of this difficulty. The subjects rated their knowledge of how diet and supplementation enhance athletic performance as either average or very good. Their primary sources of knowledge on this subject were: the Internet, periodicals and promotional materials. The role of trainers, dieticians and physiologists was relatively insignificant. Around 64% of subjects reported general use of dietary supplements, while 72.7% claimed dietary supplementation to have a positive influence on their fitness and efficiency. The popularity of supplement use depended on the character of the athletic discipline. The most frequently used supplements were, in order of popularity: vitamin and mineral preparations, creatine, carbohydrate and protein supplements, BCAA and caffeine. The subjects were convinced that supplements for athletes, despite the various contraindications concerning their use and the presence of substances banned in certain sports, are not harmful to their health. Conclusion . Use of dietary supplements by athletes is universal and depends on the type of sport played.