Neser, W. B. (Dept. Community Health, Univ. of Missouri School of Medicine, Columbia, Mo. 65201), H. A. Tyroler and J. C Cassel. Social disorganization and stroke mortality in the black population of North Carolina. Amer J Epidem 93: 166–175, 1971.—This study is an ecologic analysis of mortality rates in relationship to indicators of familial and social disorganization and poverty. To explore the hypothesized relationship between stroke mortality in relatively young Negroes and levels of social disorganization, death rates for the nine-year period 1956–1964 were obtained for North Carolina counties which were ordered and grouped by race-specific levels of disorganization. The mortality rate for county groups rose in steady increments as indices of family disorganization increased. The largest death rate differential across county groups of social disorganization was 2½ times, which was found at ages 35 to 44 years. The relationship persisted but decreased in magnitude as age increased. The findings were unlikely to be a function of either the income level or the geographic location of the counties. When mortality data were grouped by race-specific levels of disorganization for the white population, no relationship was obtained. These findings may reflect physiological responses to the constraints imposed upon subordinated members of society. This interpretation tends to conform to observations in animal studies of the effects of constraints upon subordinated members of a group-such effects as endocrine changes and increased susceptibility to disease.