Recent work has demonstrated the usefulness of employing 'avoidable' deaths as an outcome measure for assessing and comparing the effectiveness and quality of health care systems. This paper considers the relevance of 'avoidable' deaths as an outcome measure for the Spanish health system. Mortality data for 1960 to 1984, were examined and the results, with the exception of cancer of the cervix, show a marked decline in 'avoidable' deaths, consistent with studies elsewhere. This pattern of 'avoidable' deaths may reflect either a decrease in the incidence of disease or better medical management of disease leading to fewer deaths. The 'avoidable' mortality may well be a sensitive indicator of the efficacy of a country's health care system.