Emergence of infectious diseases is based on technological and environmental factors having a dramatic effect on infectious diseases. The reemergence of existing old infectious diseases which include drug-resistant forms are the major causes of worry. Infectious diseases are spreading rapidly due to demographic, ecologic conditions and population growth, increasing poverty, migration of people to urban areas are some of the reasons for the rapid spread of infectious diseases. Infectious diseases are spread through tourists, immigrants, processed food, animals that transmit diseases. Epidemiologists should work with governments of the world and draw strategies in this regard to control and prevent the spread of infectious diseases. This session discusses in detail Epidemiology of Infectious Diseases and Public Health Concerns.