A big percentage of people around the world are exposed to electromagnetic fields (EMFs); these include ELF fields emanating from electronic and electrical devices and power lines, and radio frequency radiations emanating from cordless phones, broadcasting transmission towers and cellular antennas and their towers as well. There has been increasing concern of the public over the potential health risk posed by the electromagnetic fields of these devices; this paper will discuss health risks and biological effects of EMF. The IEEE and ICNIRP have guidelines on the levels of ELF to protect the electric and electronic users from short term effects; however, these instructions do not include protection against long term effects caused by chronic exposure (Hardell & Sage 105). Cases of cancer occurring in the long term after several times of exposure of magnitudes that are below the guideline levels call for a revision of safety limits. According to research, ELF contributes to breast cancer; epidemiological studies show that breast cancer is increased by exposures to ELF. However, we cannot settle on this because there are other risk factors, such as exposure to strong sunlight and family history. Studies carried out on women in work places show that females, who are exposed to ELF of 10mG and higher, have a high risk of developing breast cancer. Also, researches on breast cancer cells show that exposure of ELF of 6-12mG affects the melatonin protective effect leading to the growth of breast cancer cells. However, other studies show that the growth of cancer cells is determined by one’s lifestyle, and this includes eating habits (Hardell & Sage 107). The exposure also affects those under cancer treatment, especially those using moxifen; this is because the exposure reduces the effectiveness of melatonin. According to research, ELF contributes to cancers and leukemia in children; epidemiological studies link increasing exposure to high level magnetic fields to increased risk of cancers and leukemia. Childhood leukemia has been connected with exposure to ELF during pregnancy or the child’s early life. However, according to other researchers, majority of children suffering from leukemia inherit it from their parents, and this fact proves that this disease is caused by chromosome abnormalities and gene mutations. Leukemia is among conditions that affect the immune system, and it might be because of exposure to chemical and various infections among others. Alzheimer is a disease of the nervous system, and high amyloid beta levels increase the risk of developing this disease. According to studies, ELF exposure increases the level of this substance, putting one at a higher risk of developing Alzheimer (Hardell & Sage 108). However, there are other factors that increase the risk of developing Alzheimer, and they include head injuries and family history of Alzheimer, among others. The nervous system of human beings, as well as that of animals, is sensitive to EMF, and its continued exposure to the same factors affects its functions. EMF of 1.0W/KG, which is lower than the allowable level, affects one’s learning as well as the memory; however, the severity of effects of exposure depends on the structure of