The exposure to power frequency magnetic fields including those resulting from electrical power substations is playing a vital role in the human biological study. This paper presents a thorough investigation into the evaluation of the internal induced electric fields and induced current densities that are induced inside the human body due to the exposure to the external magnetic fields produced by a conventional 220/66 kV power substation. The effects of different parameters such as human location, human dimensions and the incident angle of the external magnetic field on the induced electric fields and current densities inside the human body are considered, through the theoretical cases. On the other hands, a typical case is presented to account for the induction levels over the human height due to external magnetic fields corresponding to the actual measured values at different locations in the substation. Keywords: Electric power systems; High voltage; Substations; Magnetic induction; Human body