Abstract This article presents the results of radionuclide distribution in electric arc furnace process of steel production. Input materials, products and technological waste (slag and dust) are analysed. The presence of natural isotopes 40K, 226Ra, 232Th and 238U as well as of the artificial isotope 137Cs was established. Paper shows that 40K and 137Cs will be concentrated in dust, 226Ra and 238U will be mainly distributed between dust and slag but their presence in steel cannot be excluded. 226Ra and 238U in steel, slag and dust mainly come from fluorspar and bauxite. 232Th was not detected in raw materials and steel scrap but it was concentrated in slag and dust during the technological process. The measured activity in dust and slag, both artificial and natural isotopes lie within the legally permitted limits.