The induction of chromosome aberrations in human peripheral blood lymphocytes is still the most useful dosimetry system for accidental whole-body irradiation; however, in the case of a very large number of casualties the micronuclei technique might provide advantages. For partial-body irradiations, determination of hair diameter and chromosome aberrations in skin fibroblasts and hair might be advantageous, since better information on dose distribution might be obtained. The latter cytological techniques are complex and require considerable culture time. Flow cytometry for determination of chromosome aberrations, a staining technique for hair follicles and an immunochemical method for quantitative detection of persistent DNA damage in mammalian cells might be applicable in the future.