The aim of this study was to investigate the effect of acute aerobic exercise on arterial blood hemoglobin oxygen saturation in athletes.36 healthy male athletes participated voluntarily with the age (20.9 ± 1.6 yrs), weight (69.8 ± 5.5 kg) and height (169.6 ± 3.7 cm), who studied at school of physical education and practiced 90 minutes of exercise 6 days a week. This study was conducted with the approval of Ethics Committee of Health Sciences Institute with session date specified in article of Ethics Committee, dated in 13.09.2017. The heights, body weights and VO[subscript 2] max values of participants were determined by VO[subscript 2] max shuttle run test once, pre- and post-shuttle run heart rates and oxygen saturations were determined by pulse oximetry. The statistical analysis of data was made in SPSS 21.0 for windows package program. The normality test of data was done by Kolmogorov-Smirnov test, and it was found that data was not normally distributed. The Wilcoxon test, a nonparametric test, was used to determine for difference between pre-test and post-test. The significance value was taken at level 0.01. As a result of statistical analyses, it was determined that there was a statistically significant difference between oxygen saturations and heart rates of participants before and after exercise. In conclusion, it can be said that acute aerobic exercise can reduce oxygen saturation.