Background and objektives: In 1988 the German Vaccination Board (STIKO) at the Robert-Koch-Institute (RKI) in Berlin, recommended that German health care workers should be vaccinated annually against influenza. Despite this, vaccination rates have remained low (20%). Between January and March 2009 a study was performed at the University Clinical Centre in Essen to determine reasons for low influenza vaccination rates and to assess improvement strategies. Methods: All employees and staff members of the University Hospital (n = 5349) were asked to fill in a questionnaire anonymously. The completed questionnaires were digitalized and the results analysed electronically. Results: 1 670 of the 5 349 (31%) questionnaires were found to be satisfactory for evaluation. The vaccination rate among this cohort was 29%. Vaccination rates varied widely between different departments (4-71%). The most common reason for not undergoing vaccination was, forgotten" (32%). The second most common reason was the fear of side effects (30%). Only 32% of the employees stated that the quality of the information about influenza vaccination provided by their employer was, good" or, very good". Conclusion: The vaccination rate of 29% among this group of health care workers was higher than the average (20%) in German hospitals and highest among medical doctors. Strikingly enough employees of theoretic departments were vaccinated to a higher percentage than those providing nursing care and thus had more frequent contact to patients. A number of comparatively basic and inexpensive measures would be enough to increase vaccination rates significantly.