Friedreich´s ataxia is the most important recessive ataxia in the Caucasian population. Loss of frataxin expression affects the production of iron-sulphur clusters and, therefore, mitochondrial energy production. One of the pathological consequences is an increase of iron transport into the mitochondrial compartment leading to a toxic accumulation of reactive iron. However, the mechanism underlying this inappropriate mitochondrial iron accumulation is still unknown. Control and frataxin-deficient flies were fed with an iron-diet in order to mimic an iron overload and used to assess various cellular as well as mitochondrial functions. We showed that frataxin-deficient flies were hypersensitive towards dietary iron and developed an iron-dependent decay of mitochondrial functions.