In this video tutorial, Timothee Dub and Henna Mäkelä (Finnish Institute for Health and Welfare, Finland ) discussed the basics of infectious disease surveillance (event-based and indicator-based surveillance, active versus passive surveillance), as well as the advantages and limitations of each type of systems, followed by the example of how surveillance activities for TBE are conducted in Finland. By the end of this lecture, participants should be aware of the limitations and quality issues that can occur when using surveillance data for comparison and/or modelling.