In this study, it was aimed to determine the probable oxidative destruction of electromagnetic radiation sourcing of cellular phones on the kidney tissue of guinea pigs and reveal whether green tea extract has a preventive and protective effect to this damage. Malondialdehyde (MDA), nitrate, nitrite, and glutathione (GSH) levels and superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) enzyme activities were measured in the kidney tissues. For the study, 28 guinea pigs weighing 600–800 gr were chosen and divided to 4 groups each has 7 guinea pigs. Group A as the control group, it was fed with standart diet and kept under normal breeding conditions. Group B animals were exposed to 20 minutes talking for 30 days and were exposed to 23 hours and 40 minutes 900 MHz electromagnetic radiation spreading from cellular phone working of standby mode. Group C was both exposed to electromagnetic radiation and 100 mg/kg green tea extract was given orally per day for a month. Group D animals were treated orally green tea extract of 100 mg/kg/bw every day for a month. Comparing to control group, it was determined that only the levels of MDA, nitrate and nitrite were statistically increased (p≤0,001) and the levels of GSH, SOD, and GSH-Px were significantly decreased (p≤0,001) in Group-B exposed to electromagnetic radiation. It was observed that the exposure of guinea pigs to electromagnetic radiation causes oxidative stress on kidney tissues and, green tea extract as an important antioxidant has a decreasing effect to this oxidative stress in kidney tissues.