Abstract-Long term radio frequency electromagnetic field (RF EMF) exposures due to Global System for Mobile communication (GSM) frequencies were investigated in this study. 158 Swiss Albino mice in unrestrained conditions were used as surrogate and divided into four groups. The average peak field strength generated and measured inside the cages placed at a far field from the antennas is 0.6 × 10 −3 mW/cm 2 , and the specific absorption rate at 0.9 GHz and 1.8 GHz is 2.33 × 10 −3 W/kg and 1.97 × 10 −4 W/kg, respectively. Three samples of the mice chosen at random each from sham and exposed groups in week 4 and subsequently biweekly basis were taken for haematology and histopathology tests. The complete blood count result shows that haematological parameters of both the sham exposed and exposed mice were within the normal range of mice in the control group. A statistical analysis was conducted to determine whether differences observed between the experimental groups were significant. The histopathology examination on some internal organs shows that spleen and bone marrow of the mice were normal for all the three experimental groups, while a sign of tissue degeneration and inflammations were observed after 8 weeks of exposure on the brain,