Summary: In June 1998, a questionnaire was sent to evaluate the influenza vaccination practices in Switzerland: 429 health care institutions were to assess the level of influenza vaccination and the coverage of specific groups; each institution was required to specify whether vaccination coverage was known precisely (based on recorded data) or estimated. The response rate was 42.4%. Among institutions which responded, the mean accurate vaccination coverage rate for all patients was 40% and the estimated rate was 29%; these rates were slightly higher for people older than 65 years. For the entire staff, the accurate vaccination rate was 16% (14% estimated) whilst for the medical staff, the mean coverage was higher at 30% (measured) and 16% (estimated). The mean vaccination rate for patients and residents was 59% in the French speaking region of Switzerland, 54% in the Italian speaking canton, but only 37% in the German speaking region. The same ranking was found for vaccination coverage of medical staff: 21% in the French speaking region, 15% in the Italian speaking canton, and 13% in German speaking areas. These results suggest that cultural differences could play an important role in the attitudes and behaviour of the population regarding influenza vaccination programmes among the linguistic regions in Switzerlan