The implementation of spread spectrum technique within the boost type power factor corrector (PFC) for its EMI reduction is studied. The study involves the experimental measurements, SIMULINK simulations and the calculations of attenuation of harmonics of switching frequency spectrum. The results show that appreciable EMI attenuation can be achieved by the use of spread spectrum gained with sinusoidal frequency modulation. The modulating signal’s frequency and the deviation manifest themselves as the main factors that influence the degree of EMI attenuation. Some adverse affects of frequency modulation are also discussed. It has been proved, that the efficiency of PFC under study slightly decreases with the increase of frequency deviation. SIMULINK model of boost PFC was also designed. The fact that the simulation data and the experimental ones are almost identical proves that the model is relatively precise and could be used as the tool for analysis and for further investigation in order to examine other types of modulating signals and their effects. Ill. 4, bibl. 8 (in English; abstracts in English, Russian and Lithuanian).