This medical method has more than 20 years experience, microwave radiometry, is based on measuring of the intensity of natural electromagnetic radiation from patient’s tissue at IR and microwave frequencies. This intensity is proportional to the temperature of tissue. The changes in temperature (thermal abnormality), that are the basis of early detection of the cell proliferation (doubling time) in different organs, which is typical for cancer, are caused by increased cancer cell metabolism. It should be noted that thermal changes precede the anatomical changes that can be detected by traditional methods such as US (Ultrasound), X-Ray mammography, CT (Computer Tomography), MRI (Magnetic Resonance Imaging) and palpation. Thus, microwave radiometry is a very promising method for the breast and other organ cancer detection at the preclinical stage.