Background: Streptococcus pneumoniae is a significant cause of meningitis and septicemia in early infancy, being associated to a high case-fatality rates and serious sequelae. Objective: To investigate the burden of invasive disease caused by S. pneumoniae in Valencia, Spain, during a three-year period (1996-1998). Methods: Hospital-based prospective active surveillance program for invasive bacterial diseases in children ≤ 15 years of age in Valencia, from December 1, 1995 to January 1999. Results: A total of 94 cases of invasive pneumococcal disease were detected in patients ≤ 15 years of age. The overall annual incidence of invasive pneumococcal disease was 4.6/100,000 persons, ≤ 15 years of age. The incidence of invasive disease and meningitis was higher among children younger than 2 years of age (16.8 and 3.8, respectively). Serotypes 19, 14 and 6 accounted for 83% of the isolates. Conclusions: The age distribution of invasive pneumococcal disease and meningitis shows a peak in the first two years of life and a decline thereafter. Serotypes 19, 14 and 6 are those primarily responsible for invasive pneumococcal disease in children of this region of Spain. © 2002 The British Infection Society. Published by Elsevier Science Ltd. All rights reserved.