The present study has investigated the potential effects of extremely low frequency (ELF) electric field exposure on plasma cholesterol and triglyceride levels of adult male rats. Sixty rats have been divided into three independent groups randomly, 20 of which arranged as controls (without exposure to 50 Hz electric field), 20 of which have been exposed to a 50 Hz electric field for 10 days and 20 of which have been exposed to a 50-Hz electric field for 30 days. Levels of total cholesterol and triglyceride in plasma samples have been measured. Total cholesterol concentration of the plasma in group 2 with short-term exposure and group 3 with long-term exposure to 50 Hz EF (65.33 +/- 15.31 mg/dL and 59.55 +/- 15.01 mg/dL, respectively) has showed significant decrease when compared with control groups (70.44 +/- 19.60 mg/dL). Also, plasma triglyceride showed similar changes (control: 84.44 +/- 16.79 mg/dL, 67.33 +/- 15.63 and 51.53 +/- 14.17 mg/dL in group 1 and 2, respectively). Fifty Hz electric field may decrease plasma total cholesterol and triglyceride levels in rodents significantly, especially with long-term exposure.