OBJECTIVE To estimate the burden of disease due to vaccinable diseases and the relative importance of these diseases in the health of the Spanish population aged less than 15 years old. METHODS Disease burden was measured in disability-adjusted life years (DALYs). DALYs were computed by adding years of life lost (YLL) to years lived with disability (YLD). The DALYs of the Spanish population aged less than 15 years old were estimated for 1999 and were stratified by diseases according to the classification system of the Global Burden of Disease (adapted to the aim of the study), age group and gender. Diseases included in the childhood vaccination schedule, varicella, and pneumococcal disease were targeted for this study. The sources used were: the national mortality register to compute YLL, the Epidemiologic Surveillance National Network, hospital discharge data (CMBD) and the scientific literature to compute YLD due to vaccinable diseases, and World Health Organization estimates (Euro-A) or, when these were lacking, morbidity hospital data (Hospital Morbidity Survey) to compute the YLD due to non-vaccinable diseases. RESULTS The burden of disease due to vaccinable diseases was 1.2% of global DALYS (the overall DALYs rate was 46,57/1,000 habitants): excluding meningococcal disease (0.5% to 3.3%), diseases included in the vaccination schedule represented 0.00% to 0.03%, depending on age groups, except meningococcal infection (between 0.5% and 3.3%). Pneumococcal meningitis represented 0.06% to 0.65% and varicella 0.00% to 0.15%, also depending on age groups. CONCLUSIONS Disease burden due to vaccinable diseases is a good indicator of the health of the young population in Spain. This measure summarizes and combines information on mortality, morbidity and disability caused by diseases. The DALYs attributable to diseases included in the vaccination schedule demonstrate that immunization programs have achieved their goals.