The high voltage transmission and distribution lines are a source of electromagnetic fields.The human exposure to high frequency electromagnetic fields from mobile phones(300 MHz 3 GHz),is also source of risk of the living organisms.To study the biological effects of electromagnetic fields produced by high voltage power transmission lines, MATLAB program package is used for mathematical calculations of the distribution of the EMF in human body under high voltage transmission lines.The work includes experimental tests on experimental animals.Blood samples from experimental animals are taken after two, four, six and eighteen weeks. Blood analysis of G.O.T,complete blood picture and total serum proteins are taken to study the effect of EMFs on living organics of rats.From the work done . It is concluded that, the blood level of SGOT of tested animals is high and affect liver, muscle tissue, kidneys, heart and red blood cells,the account of red blood cells (erythrocytes or RBCs) indicates that exposing to electric field for long time may cause leukemia, total serum protein in tested group is decreased and this affect,liver and heart.