A high proportion of the population of Tecumseh, Michigan, participated in comprehensive assessments of health, personal habits, and socioeconomic status during the periods 1959–1960 and 1962–1965. A total of 5735 persons older than 20 years of age, comprising 2749 men and 2986 women, form the subjects of this report Diabetics were identified at entry and contrasted to nondiabetics with respect to personal characteristics. During the period 1977–1979, health status of 69% of the eligible cohort was ascertained. Age, adiposity, and blood glucose level were the principal predictors of new cases of diabetes. Family history was a significant predictor only among middle-aged, overweight men. Diabetes tended to be related to central fat distribution as Indicated by subscapular skinfold thickness. Predictors of new cases of diabetes were not necessarily related to prevalence of the disease in this population.