Hereditary hemochromatosis can cause individuals to absorb too much iron from their diet. Higher tissue iron content, below the threshold of toxicity, may enhance oxygen carrying capacity and offer a competitive advantage. Single nucleotide polymorphisms (SNP) in the homeostatic iron regulator (HFE) gene have been shown to modify iron metabolism and can be used to predict an individual's risk of hemochromatosis. Several studies have shown that HFE genotypes are associated with elite endurance athlete status; however, no studies have examined whether HFE genotypes are associated with endurance performance. The objectives of this study were to determine whether there was an association between HFE risk genotypes (rs1800562 and rs1799945) and endurance performance in a 10-km cycling time trial as well as maximal oxygen uptake (V˙O2peak), an indicator of aerobic capacity. Competitive male athletes (n = 100; age = 25 ± 4 yr) completed a 10-km cycling time trial. DNA was isolated from saliva and genotyped for the rs1800562 (C282Y) and rs1799945 (H63D) SNP in HFE. Athletes were classified as low risk (n = 88) or medium/high risk (n = 11) based on their HFE genotype for both SNP using an algorithm. ANCOVA was conducted to compare outcome variables between both groups. Individuals with the medium- or high-risk genotype were ~8% (1.3 min) faster than those with the low-risk genotype (17.0 ± 0.8 vs 18.3 ± 0.3 min, P = 0.05). V˙O2peak was ~17% (7.9 mL·kg-1⋅min-1) higher in individuals with the medium- or high-risk genotype compared with those with the low-risk genotype (54.6 ± 3.2 vs 46.7 ± 1.0 mL·kg-1⋅min-1, P = 0.003). Our findings show that HFE risk genotypes are associated with improved endurance performance and increased V˙O2peak in male athletes.