Pneumococcal vaccine is effective in preventing invasive pneumococcal disease in adults >or=65 years of age, but it is not widely used in Western Europe. In this study, data from an earlier (1995) cost-effectiveness study on Belgium, France, Scotland, Spain, and Sweden are updated, and data on five new countries--Denmark, the UK (specifically, England and Wales), Germany, Italy and The Netherlands--are added. Epidemiological and economic variables specific for each country were used, and it was assumed that pneumococcal and influenza vaccines would both be administered during the same physician visit. In the base-case analyses, the cost-effectiveness ratios ranged from euro 9239 to euro 23,657 per quality-adjusted life-year. Because the incidence and mortality of invasive pneumococcal disease were underestimated in most countries, a country-by-country analysis was performed, assuming an incidence of 50 cases per 100,000 population and mortality rates of 20, 30 and 40%. For a mortality of 20%, the cost-effectiveness ratios ranged from euro 4,778 to euro 17,093, and for a mortality of 30%, they ranged from euro 3,186 to euro 11,395. Pneumococcal vaccination to prevent invasive pneumococcal disease in elderly adults was very cost-effective in all 10 countries. This evidence justifies the wider use of the vaccine in Western Europe.