[Factors determining infant mortality in Spain]

We introduce an ecological research for Spain between the 1975 and 1979, trying to explain the variation of childhood mortality. The social-economical factor had an important weight, as the disposable familiar rent (R2 = 0.44) and the per capita rent, while the health factors had a least important influence. From this last group, the health resources utilization were the most important, as the consultation per habitant (partial regression coefficient -0.15 and -0.14 in 1977 and 1978 respectively) and the surgery activities. Every this reflect a country in change.