In this article, the biological effects of RF and MW radiations (3 kHz–300 GHz) are discussed with emphasis on potential hazards. Most of the modern communication equipment occupies the range 1-40 GHz. A person is supposed to expose near the locations of radio, television transmitters, mobile base stations and wireless networks. This paper investigates the possible effects on human health of exposure to RF / MW radiations. The suggestions / rules framed by different international organizations are briefly sketched in this article.