Fanconi Anemia (FA) is a syndrome associated with chromosomal fragility. Current laboratory tests to diagnose this disease are based on the scoring of chromosomal aberrations induced in peripheral blood lymphocytes by clastogenic chemical agents, mainly: diepoxybutane (DEB) or mitomycin C (MMC). This study evaluated an alternative test for the diagnosis of FA, in which ionizing radiation replaces DEB/MMC. Two groups were studied: normal and DEB-sensitive individuals. From each individual, samples of peripheral blood were irradiated using an electron linear accelerator. Following lymphocyte cultures, and slide preparation, metaphases were scored based on the same methodology for biological dosimetry, according to recommendations of the International Atomic Energy Agency. Our results emphasized a pattern of distribution of dicentrics, fragments, as well as abnormal chromosomal arrangements. The methodology of analysis here proposed permitted to distinguish normal from DEB-sensitive subjects.