We initiated the present work to determine whether the presence of the HFE C282Y or H63D mutations could be related to the clinical expression of diabetes mellitus type 2. Two hundred and twenty five type 2 consecutive diabetic patients were included and the HFE genotypes were determined. Younger ages of onset of diabetes as well as a longer duration of the disease were detected in patients carrying at least one C282Y allele (p = 0.007). An increased prevalence of retinopathy (p = 0.014) and of nephropathy (p = 0.04) were also detected in individuals carrying at least one C282Y allele in comparison with patients carrying the other alleles. The increased prevalence of retinopathy in C282Y carriers is related to the increased duration of the disease, but we not have detected that the prevalence of nephropathy is associated with the duration of the disease. However, multivariate logistic regression confirms that the prevalence of nephropathy is higher in the group of patients carrying at least one C282Y allele or the H63D/H63D genotype as compared to the group of patients with the wild-type (N/N) or the N/H63D genotype. To our knowledge our study is the first one to report an earlier age of onset in type 2 diabetic patients carrying HFE mutations.