Electromagnetic waves (EMF) are a mixture of electrical and magnetic waves. The energy transmitted by these radiations is absorbed by living tissues. Electromagnetic fields seem to cause infertility in women. Cannabis is annual herbaceous plant grows in tropical areas. This study was conducted to investigate the protective effects of hydroalcoholic extract of Cannabis sativa in various doses of 50, 100 and 150 mg / kg on the damages induced by electromagnetic fields of 50 Hz and 50 Gauss, on the puberty of ovarian follicles and levels of FSH, LH, estradiol and progesterone hormones in NMRI immature mice. In this study, 48 NMRI immature female mice with an approximate age of 16 days and approximate weight of 18 grams were divided into 8 (experimental, sham, positive control and negative control) groups. After the treatment, the ovaries were extracted and weighed, and sections with H& E staining, the number of primordial, primary, secondary, and atretic follicles were counted, and the level of hormones have been done. The results showed that the concentration of 50 mg / kg of cannabis extract after the exposure to electromagnetic field of 50 Gauss could increase the number of follicles and reduce the number of atresia follicles. The group treated with the concentration of 50 mg / kg of cannabis extract after the exposure to electromagnetic field of 50 Gauss showed increased levels of FSH, LH and estradiol hormones (p <0.01) and a reduced level of progesterone (p <0.01). Therefore, the concentration of 50 mg / kg of cannabis extract have a protective role in preventing infertility due to ovarian tissue damages induced by electromagnetic fields.