This is the basic study for the consolidation of the service system regarding to the medical, health & welfare that would be corresponded to the needs of the senile dementia aged and their families. The investigation had been executed against the aged lived in the whole area of Sendai by the teams of the speacialists of psychiatrists and public health nurses. The results of this study are summarized as follows; 1. We could acquired that the ratio of the senile dementia aged is 5.02 percents and the senile dementia aged at home is 4.48 percents against to whole aged. 2. We estimated the ratio of the senile dementia aged on the each types that had been classificated into six types in the former report by the combination of life states on the senile dementia aged such as their household states & behavior abilities. It was seized that the required care service aged who became to the conditions of senile dementia appeared very high ratio. 3. The states of life and the bodily conditions of the aged were confrontated to the degrees of senile dementia. Therefore, it have been elucidated that cares & helps for the aged are became to serious with the progress of senile demenntia. And then, burdens of families would be increased more than before. 4. It was very difficult that the demands of the senile dementia aged and their families would be socilized. The other hand, demands that could be socialized were difference by their degrees of senile dementia. 5. The conclusion by the public health nurses is that welfare servics is to be required to the form of the care service at home than their families helps. Therefore, completion of qualities and quantities on the care service at home is the urgent matter to be settled first.