A survey of diabetes mellitus was undertaken among the population of farming and fishing villages. Among 1,326 men and 1,747 women above forty years ages, the incidence of diabetes mellitus detected was as follows : 4.2 per cent in men of ages 40 to 49, 6.2 percent in 50 to 59, 10.5 per cent in 60 to 69, 17.1 per cent in 70 to 79 and 10.0 per cent above 80