Background: None of the genetic markers are selectively associated with elite athletes, but potential candidates are found in the renin-angiotensin system, which plays a key role in the regulation of cardiovascular physiology. The most extensively examined gene in connection with the hemodynamics category is the angiotensin converting enzyme (ACE). This review paper has focused on ACE I/D allele polymorphism regarding the evidence of the effects of physiological and pathophysiological drugs and has completed with an original work in the exercise physiology. Methods: In this study we examined genetic polymorphisms of ACE in female (n=26) and male (n=24) athletes as well as in a well-trained control group (n=24). MVVex, VE and VO2max were determined at rest and during an exhaustive step test. Results: The frequency of the ACE I allele was significantly higher (p < 0.041) in the group showing a higher intensity of breathing metabolism. The ACE D allele frequency was significantly higher in the excellent endurance athletes group than in unsuccessful athletes (p < 0.054). Conclusion: The ACE I allele is a genetic marker for higher endurance efficiency in acute physical activity and higher adaptation of the cardiovascular system. The measurement of acute physical status needs to be completed with examination of genotype, which is related to the athletic excellence also, because the D allele could be associated with good performance by endurance athletes in future world championships. Further studies are needed to assess the view that the ACE D allele has a significant role in athletic efficiency.