The variable clinical manifestations of cystic fibrosis (CF) suggest the influence of modifier genes. Genetic and environmental factors that determine whether an individual will develop associated complications are still being determined. It has been proposed that the gene for hemochromatosis, HFE, may be a modifier locus for CF disease phenotype. Recent research has suggested a relationship between mutations to the HFE gene and the development of meconium ileus (MI) and liver disease in CF. This study aims to expand our knowledge of the HFE mutations C282Y and H63D carrier rate in an Irish population of CF allele carriers. PCR restriction enzyme analysis was performed on blood samples from CF patients to identify the C282Y and H63D mutations. HFE status of CF allele carriers and CF patients (Delta F508) homozygotes with and without meconium ileus was determined. The carrier frequency for C282Y was 30.8% for the Delta F508 homozygote MI positive group, as compared to 12.5% for the non-Delta F508 MI positive group but did not reach statistical significance (p = 0.27). Interestingly, no Delta F508 homozygote patients were homozygous for the C282Y mutation.