BACKGROUND: This study aimed at describing influenza vaccination coverage among Spanish children, adults and health care workers (HCWs). PATIENTS AND METHODS: We analyzed 27,791 questionnaires on subjects aged 6 months or over, drawn from the 2003 Spanish National Health Survey. As the dependent variable, we took the answer to the question, "Did you (or your child) have a flu shot in the last campaign?". Independent variables were age group, gender, nationality, occupation (HCWs) and coexistence of chronic conditions. RESULTS: Overall influenza vaccination coverage for the total sample was 19.58%. Coverage for the pediatric population was 5.55%, with 20.74% of those with and 4.67% of those without chronic condition being vaccinated. Vaccination coverages were: 63.7% among subjects aged >/= 65 years; 30.5% among high-risk subjects aged < 65 years; and 19.65% among HCWs. CONCLUSIONS: We conclude that the available results show low levels of influenza vaccination coverage among high-risk subjects aged under 65 years, children in particular, and HCWs.