There is increasing evidence regarding the association between mitochondrial DNA (mtDNA) and aerobic capacity; however, whether mtDNA haplogroups are associated with the status of being an elite endurance athlete is more controversial. We compared the frequency distribution of mtDNA haplogroups among the following groups of Spanish (Caucasian) men: 102 elite endurance athletes (professional road cyclists, endurance runners), 51 elite power athletes (jumpers, throwers and sprinters), and 478 non-athletic controls. We observed a significant difference between endurance athletes and controls (Fisher exact test = 17.89, P = 0.015; Bonferroni’s significant threshold = 0.017). yet not between power athletes and controls (Fisher exact test = 47.99, P = 0.381) or between endurance and power athletes (Fisher exact test = 5.53, P = 0.597). We observed that the V haplogroup was overrepresented in endurance athletes (15.7%) compared with controls (7.5%) (odds ratio: 2.284; 95% confidence interval: 1.237, 4.322). In conclusion, our findings overall support the idea that mtDNA variations could be among the numerous contributors to the status of being an elite endurance athlete, whereas no association was found with elite power athletic status. (C) 2011 Elsevier B.V. and Mitochondria Research Society. All rights reserved.