Mice Leydig cells were irradiated by 1950 MHz radio frequency electromagnetic field (sXc irradiation system, GSM talk signal, with the frequency of 1950 MHz, and SAR value of 3 W/kg). After continuous irradiation for 24 h, the irradiated or sham-irradiated cells were seeded in 96-well plates and 10 cm dishes, respectively. The cell proliferation, cell cycle and cell apoptosis were measured by using CCK8 assay and flow cytometry, respectively. The results showed that cell proliferation in the irradiated group was slower than that in the sham-irradiated group 2−9 d after irradiation (p<0.05); cells in S phase in the irradiated group increased significantly compared with the sham-irradiated group 1 d, 2 d, 3 d, 4 d and 5 d after irradiation (p<0.05); cells in G1 phase in the irradiated group decreased significantly compare with the sham-irradiated group 3 d and 5 d after irradiation (p<0.05). There was no significant difference in cell apoptosis between the irradiated group and the sham-irradiated group. 1950 MHz RF EMR for 24 h may inhibit the cell proliferation of TM3 cells by changing the cell cycle, yet further study is needed to explore the specific mechanisms of this phenomenon.Cited