The health and economic costs and benefits of vaccinating a cohort of 60,000 children born in Catalonia in the year 2000 with the pneumococcal 7-valent conjugated vaccine were compared with the alternative of not implementing the vaccination programme. The time horizon fixed for the programme was 10 years for invasive disease, 2 years for all episodes of pneumonia and otitis media and 3.5 years for the placement of tympanostomy tubes. In the base case (incidence rate of invasive disease of 160 per 100,000 and price of the vaccine 50 euros) the net present value was negative, both from the societal perspective (-5.1million euros) and from the provider's perspective (-9.2million euros). The benefit-cost ratio was 0.59 euros from the societal perspective. The cost per disability adjusted life year (DALY) gained was 44,307 euros from the societal perspective and 80,291 euros from the provider's perspective.