The paper considers the level of the extremely low-frequency magnetic field produced from the portable computers to the humans. In this way, the magnetic field characterized by the low frequencies up to 300 Hz has been measured. The experiment consists of testing 10 different portable computers in normal condition and under stress. The measuring of the magnetic field is performed in the adjacent neighborhood. The measured data are presented and discussed as well. They are compared with the critical values suggested by MPR II, TCO, ICNIRP, the Serbian Ministry of Environment, Mining and Spatial Planning, and critical values given in the literature. It is shown that some of portable computers get a very strong magnetic-field  radiation. Hence, it is recommended to be used with caution.