[en] The effects of the external magnetic field has been investigated on the K XRF cross sections of Fe, Co, Ni, and some of their compounds by using an energy dispersive X-ray fluorescence spectrometer. The samples were irradiated by using the γ-rays of 59.537 keV emitted from an ²⁴¹Am radioisotope source of 100 mCi. The samples were prepared from pure foil of Fe, Co, Ni, and some of their compounds. The external magnetic fields have been applied two opposite directions and the magnitude of the external magnetic field has been fixed at 0.400 T and -0.400 T. The measured K XRF cross sections have been compared with the calculated theoretical data and interpolated values of PURI et al. Our experimental results show that the K XRF cross sections have been affected by the external magnetic field. (author)