The aim of this paper is to review the current literature on electromagnetic radiation (EMR): physical, biophysical, and telecommunication. The widespread application of EMR in modern technologies requires telecommunication and healthcare professionals to possess some knowledge of its physical and biological properties. In this review article, we will discuss biophysical principles of EMR, its interactions with living organisms and its application in clinical practices. We will discuss here beneficial as well as hazardous effects of EMR. We will also discuss the safety guidelines.