Infectious Diseases is a recognised clinical specialty in almost all European countries, in the United States of America, Canada and most countries in Central and South America. Even though the training programs are heterogeneous in the different European countries, the Infectious Diseases section of the UEMS (European Union of Medical Specialties) is working to harmonise them. In 1998, the European Board of Infectious Diseases recommended a 6-year training period, similar to that of other medical specialties, including 2 years of general internal medicine training and 2 years of specific training. The clinical activity and services provided by Infectious Diseases units in Spanish hospitals is similar to that in other countries. In this article, training programs, clinical activity and scientific activities in Infectious Diseases in the different countries is reviewed.