[en] Assumption that environ-mental agents including radiation are responsible for a large percentage of cancer remains widespread. The development achieved in molecular biology and biochemistry makes possible to assess the existence of this relationships. The finding that radiation could be carcinogenic in humans, can be followed by the demonstration that radiation ia capable for cousing the kind of genetic damage, that coud be investigated by the emerging technique of mutational spectrometry. Firstly, hypoxanthine - guanine phosphoribosyl transferase (HPRT) gene is irradiated, followed by selection of mutant cells and the isolation of DNA. Finally the DNA was amplified by PCR technique and characterized by electrophoresis thereafter. The specific mutants will be present as sharp ''bands'' on the gel. Mutational spectra of the specific mutagen will be observed as a series of characteristic bands. In this review the mutational spectrometry technique will be described more detail