The results refer to a 12-year longitudinal population study of women in Gothenburg, Sweden. Correlations were studied between initial adipose tissue amount and adipose tissue distribution on the one hand and incidence of diabetes and change in serum blood glucose concentration on the other. Body mass index, sum of two skinfolds and waist-to-hip circumference ratio were significantly associated with incidence of diabetes. The waist-to-hip ratio was also positively associated with an increase of serum glucose concentration in the fasting state during the followup period. The significant correlations remained in multivariate analysis and were independent of age, initial smoking habits, systolic blood pressure, intake of antihypertensive drugs and serum cholesterol, triglyceride and glucose concentrations. The correlations between the separate anthropometric variables and incidence of diabetes remained when the other anthropometric variables were considered as background factors. The distribution of fat to the abdominal region as well as the total amount of fat per se seem to be important risk factors for diabetes and the effect of one of these factors seems to add to the other.