The impact of the Finnish health services on mortality from natural causes amenable to interventions by them was estimated for the period 1969 to 1981. During this period, mortality from amenable causes fell by 63% among males and 68% among females aged 64 years or less. The respective decreases for non-amenable natural causes of death were 24% and 29%. The rate of decline in mortality from amenable causes was similar for the two sexes. It was assumed that the decline in mortality from nonamenable causes reflects the joint influences of environmental, social, nutritional, and genetic factors and that the difference between this and the decline in mortality from amenable causes approximates to the true effect of the health services. Health services were estimated to account for 50% of the total decline in mortality from amenable causes for both sexes.