In addition to reducing physical activity, we have a significant increase in living standards, which also increases the risk of developing overweight. Therefore, fitness as a physical activity, as a tool in terms of movement therapy, is increasingly finding application in contemporary life. With the increase of interest for fitness there is also the interest for the use of dietary supplements among the population which performing fitness.The purpose of this paper is to assess the prevalence of use of dietary supplements in people who exercise in fitness centers, what are the reasons for their use and the types of supplements used by them. The Hi-square (x2) test is used to determine if there is a significant difference between the expected frequencies and the observed frequencies. The results obtained show that the majority of respondents use supplements (78%), and that the source of information about the use of supplements in fitness is the fitness instructor with 56%.Among the reasons for applying supplements in fitness is the reduction of fat mass by 70%, weight loss by 70% and replacement of food deficiencies 46%. The most used supplements are Casein (protein) with 58%, L-carnitine / body attack (weight loss) with 34%, Fish oil omega 3 with 30%, Hydraxycut -elite (weight loss) with 26%.It has been 21proven that with the increase of interest of female persons for fitness, their interest for the use of dietary supplements has also increased.