This study clarified the relationship between social interaction and mortality using a five year longitudinal study. The subjects were all 60 years or above who lived in a farming community near major urban centers in Japan (n = 1,069). A total of 153 subjects died within the five year period after the baseline survey. A questionnaire was utilized, the contents of which were about social interaction (using the "Index of Social Interaction" which consisted from 5 subscales: Independence, Social curiosity, Interaction, Feeling of Safety, and Participation in the society), health status, life style, and subjects' feeling about themselves. The results were as follows: 1) low score on "Index of Social Interaction" was significantly related to five-year mortality, 2) the mean score of "index of Social Interaction" of deceased was significantly lower then survived subjects aged 75 and over, 3) logistic regression analysis adjusted for age, sex, length of education, and health status revealed that odds of mortality were significantly high with lower score in the Index of Social Interaction.