Low-Intensity Pulsed Ultrasound Stimulus (LIPUS) accelerates the bone fracture healing in animal models and in clinical studies. In this work, according to the literature, we have chosen the mesenchymal stem cells (MSCs) as precursors of bony tissue, in particular the MSCs derived from the human ovarian follicular liquid (FL), and we have investigated the effects of ultrasounds on their proliferation. We tested two different durations of ultrasound stimulus (2 and 5 min) and compared these data to the control without ultrasound treatment. To quantify the proliferation of these putative MSCs, we used the BrdU incorporation assay: in comparison with the control, the results showed that 5 min of ultrasound stimulus significantly increased the percentage number of cells in intensive proliferative activity; on the other hand, there was no significant difference using 2 min of stimulation, hypothetically because the transmitted energy was not sufficient to stimulate the cells and to consequently enhance their proliferation. In conclusion, the effects of LIPUS on putative MSCs derived from ovarian follicular liquid show potential developments in biotech or medical applications.