[en] It has been known that protoporphyrin(PP) could be accumulated in tumor tissue and its complex with cobalt inhibits the growth of undifferentiated cells. Preparation of ⁵⁸Co-PP has been carried out using Co-58 labelled CoCl₂ in glacial acetic acid and PP in CHCl₃-pyridine mixture. It has been studied the influence of CoCl₂ as carrier and time of heating against the labelling efficiency and chemical yield. Chemical and radiochemical analysis using thin layer chroamtography(TLC) and high performance liquid chromatography(HPLC) show-ed that the complex was pure enough with 98.50% radiochemical purity. This complex has absorption bands in the vissible region at 531.8nm and 565.0nm and in Soret region at 415.6nm in methanol. (author)