Purpose: South East European (SEE) countries presented different influenza surveillance systems based on universal surveillance for influenza, different influenza diagnostic capacities and some of them less data compared to other European countries. The aim of the study was to identify influenza surveillance systems in SEE countries and challenges related to establish sentinel surveillance systems. Methods & Materials: The surveillance of influenza and specifically influenza-like illness (ILI), acute respiratory illness (ARI), severe acute respiratory infections (SARI) and virological surveillance were assessed by using Sentinel surveillance system review tools and Sentinel SARI surveillance: Scaling implementation of WHO Regional Office for Europe guidance for sentinel influenza surveillance in humans and CDC International Influenza Surveillance Assessment Tool. The tools and questionnaires were translated and adapted into countries and discussed into focus groups of profesisonals and stakeholders. A desk review was performed by a national and international team. Data collesction were analysed based on WHO Euro Guideliness for sentinel influenza surveillance. Results: All countries had virological surveillance and had capacities to use molecular diagnostic methods for influenza diagnosis. All countries had universal ARI surveillance and influenza activity was measured by laboratory-confirmed cases. Only 50% of the countries had ILI sentinel surveillance. SARI sentinel surveillance was established only in 44% of the countries. Virus isolation and identification was missing in 44% of the countries. Baseline and epidemic thresholds to indicate a level of disease activity were developed only in some countries. Only three countries had web based ARI surveillance systems but the challenges of influenza surveillance data base management were enormous and shared by all countries. Only three countries had systems to monitor and strengthen influenza surveillance but even such systems were not well developed. Avian influenza surveillance activities were lacking in cross border areas since 2010. Conclusion: None of the countries had performed assessment of their influenza surveillance system as a crucial activity for monitoring the timing and severity of influenza and documenting the change in the epidemiology of influenza infection. The countries need to increase their capacities on ILI sentinel surveillance especially to establish and improve SARI surveillance and their database management systems.