Infectious Diseases in Finland 2012 gives an overview of the most important epidemics of the year as well as of the prevalence of infectious diseases in general. Covered topics include respiratory and gastrointestinal infections, hepatitis infections, venereal diseases and microbial resistance. In 2012, major outbreaks and new findings included the following: an EHEC epidemic caused by unpasteurized milk and animal contact resulted in the intensive care of several children an increase in dengue infections was detected among travelers, notably from Madeira as a new source of infections one third of all gonorrhea infections were found to be related to foreign travel microbial resistance of gram-negative enterobacteria continued to increase with some of the bacterial strains originating from abroad. Annual data are compared with previous years allowing the reader to follow the long-term trends on the prevalence of infectious diseases. Data are compiled from the Infectious Diseases Register maintained by the National Institute for Health and Welfare.