Objectives: To characterise the nature, content, and performance characteristics of existing national STI surveillance systems in the European Union (EU) and Norway, to facilitate collection of comparable surveillance data. Methods: Cross sectional survey using a structured questionnaire. Results: Case reporting from clinicians and/or laboratories is the mainstay of EU surveillance systems for bacterial STIs. Coverage of case reporting varies from less than 10% to over 75%, and lack of and/or heterogeneity in case definitions affect the relative specificity and sensitivity of reporting systems. Considerable variations also exist in STI care sites; the populations who use these services; and in partner notification practices, STI screening practices, and STI laboratory diagnostic tests employed, affecting the representativeness of reported data and the sensitivity of surveillance systems for detecting the true number of STI cases. Conclusions: The heterogeneity of current surveillance systems complicates direct comparison of STI incidence rates across Europe. Introduction of standardised case definitions for reporting, and increased coverage of mandatory reporting systems where necessary, are needed. Definition of standardised minimum datasets and use of sentinel and enhanced surveillance systems to supplement universal case/ laboratory notification data, could improve our understanding of the distribution and determinants of STIs across Europe, and aid in the design of effective public health responses. In the context of the changing epidemiology of STIs, systems for detection and monitoring of localised outbreaks of acute bacterial STIs (syphilis and antimicrobial resistant gonorrhoea), as well as prevalence monitoring systems for frequently asymptomatic STIs (chlamydial infection and viral STIs), are also necessary.