The effect of the pneumococcal conjugate vaccine immunization programme on pneumococcal-associated or potentially pneumococcal-associated hospital admissions in the Italian region of Liguria was assessed. Hospital admission rates were compared in subjects belonging to birth cohorts before and after the introduction of widespread immunization for 0 - 2-year old children with a seven-valent conjugate vaccine (PCV7). Significant reductions in hospitalization rates for all-cause and pneumococcal pneumonia and for acute otitis media were observed in subjects born after widespread uptake of the vaccine. The preventive fraction (a measure of vaccine effectiveness) ranged from 15.2% for all cause pneumonia to 70.5% for pneumococcal pneumonia. This study contributes to the growing body of information that supports the beneficial effect of PCV7 vaccination.