Serotonin, which is the most important biomarker affecting human psychology, can also negatively affect the athletic performance of the athlete. The aim of our study was to examine the distribution of “S” and “L” alleles in the promoter region of the SLC6A4 gene associated with anxiety in healthy professional football players. 19 professional football players between the ages of 15-29 who actively used a training program for at least 4 days a week and 45 individuals who did not use any exercise program (control group) participated in our study. After obtaining the necessary ethics committee permissions, consent forms describing the results and outcomes of the study protocol were signed by the participants. Afterwards, intraoral epithelial cells were taken from individuals who participated in our study, and DNA isolation was performed. Genotyping of all polymorphisms was determined using the polymerase chain reaction (PCR) method. The numbers and percentages of the LL, LS, SS genotypes of the SLC6A4 gene in the football players participating in our study were determined as 11 (57.8%), 4 (21.1%), and 4 (21.1%), respectively. In our study cohort, 26 (68.4%) L allele and 12 (31.6%) S allele were observed. When the promoter region of the SLC6A4 gene was examined in our study cohort, LL genotype was found to be dominant, while the L allele was found to be higher than the S allele. In the control group, the same genotype number and percentages were determined as 12 (26.7%), 24 (53.3%) and 9 (20%), respectively. In the control group, the allelic distribution was observed as 48 (53.3%) for the L allele and 42 (46.7%) for the S allele. While genotype distributions (p=0.0001) were found between the athlete group and the control group, statistically significant difference was found between both groups by their allelic distribution (p=0.0425). As a result, it was concluded in our study that the determination of SLC6A4 promoter polymorphisms may help prevent anxiety and cognitive anxiety in athletes in the early period.