The effect of nanosecond repetitively pulsed microwave radiation (RPM, 50–4000 pulses, pulse repetition rate of 13 Hz, peak power flux density of 140 W/cm2, carrier frequency of 10 GHz) on the stimulation of me-senchymal stem cells (MSC) proliferation was studied. The effect of exposure was assessed by the change in the number of cells in the culture after a single irradiation with a different number of pulses. The most pronounced effect exerted by the impact with 100 and 50 pulses, and the effect is realized with a maximum speed after 24 hours.