Abstract: The aim of this study was to investigate the preventive effect of zinc on count, motility and fertilization capacity of rat spermatozoa that exposed to 1.5 Tesla magnetic fields. Thirty two adult male rats were subdivided randomly to 4 groups: group 1, serve as untreated controls; group 2, was exposed to the magnetic field for 30 min but received no additional treatment; groups 3 and 4, were exposed to a magnetic field for 30 min and received 200 and 500 ppm zinc sulfate oral daily, respectively. After 50 days all rats were killed and their epidydimises were removed. Then after incubation of sperm in the incubator within 37°C and 5% CO2 for 1 h, the sperms count and motility were examined by an inverted microscope. For in vitro fertilization at first the sperm suspension of different groups of rats added to the freshly ovulated ova than combined sperm-oocyte suspension was incubated for 4-6 h. Sperm counts in 1 g of the epididymis were 2998.7±322.70 in group 1 and in groups 2, 3 and 4, 1022.9±128.66, 1978.4±457.79 and 2126.1±308.90, respectively. Therefore, group 2 has a significant lower sperm count in comparison with other groups (p<0.05). Sperm with progressive motility was 52.25±3.88 in group 1, 22.35±1.82 in the group 2, 49±26±1.66 in group 3 and 46.11±4.05 in group 4. Therefore, group 2 has a significant lower sperm motility in comparison with other groups (p<0.05). The same results were obtained in the case of pregnancy. The sperm count, motility and fertilization capacity may be preserving by zinc supplementation. Therefore, zinc might have the potential for usage for MRI patients as well as workers.