Based on data drawn from the 2003 National Health Survey (NHS), we sought to: (1) estimate influenza vaccination coverages among Spanish diabetic adults; (2) analyze which sociodemographic, health-related, and use of health-care services variables were associated with the likelihood of Spanish diabetes sufferers being vaccinated; and (3) analyze the time-trend in coverage for the period 2001-2003. We analyzed data on the 1295 adults suffering diabetes included in the 2003 NHS. The reply to the question "Were you vaccinated against influenza in the last vaccination campaign?" was taken as the dependent variable. Vaccination coverage was calculated and the influence of sociodemographic, health-related, and use of health-care services variables assessed. The proportion of vaccinated diabetic adults in 2003 amounted to 57%. Multivariate adjustment showed that the variables which increased the likelihood of being vaccinated were: higher age; male gender; presence of respiratory or heart diseases; and physician visits in the last 2 weeks. Influenza coverages had significantly increased from 2001 (48.8%) to 2003. We conclude that influenza vaccination coverages among Spanish diabetic adults have improved but still remain below desirable levels and, thereby making it necessary for strategies to be implemented aimed at improving the use of influenza vaccine among diabetic patients, especially those less than 50 years, females and without other chronic conditions.