Developing technology and industry and increasing application of electromagnetic fields in medicine, threaten the environment and human health. Biological effects of these fields depend on the field magnitude and physical characteristics of exposed tissue. In order to research the effects of electromagnetic fields on kidney tissue on electromagnetic field generator was made with intensities of 0.013µT, 5 Hz and 0.207 µT, 50 Hz. 36 adult male Guinea pigs were divided into 6 groups. Group A as the control group exposed to nil electromagnetic field for two hours per day for 5 days duration , group B exposed to 0.013µT in 5 Hz to the same duration period , group C exposed to 0.207 µT in 50 Hz in similar condition , group D exposed for four hours per day for 5 days in 0.013 µT , group E tested in 0.207 µT as group D , group F used as the control group exposed for four hours per day in nil electromagnetic field .In fifth day after killing the animals, specimens were taken from their kidneys’ tissue. Then the specimens were fixed in formalin and after providing 5µm slices of them and staining them with Hematoxilin – Eozin they were examined. The results showed that D and E groups of electromagnetic fields led to swelling in epithelial cells of kidneys’ tubules and subsequently cell necrosis that caused to decrease in kidney lumanial tubules. Also glumerulia expanded and adhered to Bumans’ capsule. Electromagnetic fields having waves with high energy cause a rise in local temperature and as ionizing rays cause cell damage through creating free radials. In connection with glumeruli expanding, articles confirm that electromagnetic fields cause anemia, eventually in order to compensate this decrease, glumerulia were expanded.