Investigated the personal models of diabetes held by 46 female outpatients with non-insulin-dependent diabetes mellitus. The subjects' mean age was 64 years (range = 46 to 79 years), and 24 subjects were taking insulin. Their personal models were explored by using a comprehensive interview including questions on beliefs and emotions about cause, symptoms, course, treatment, and consequences of their diabetes. Two weeks after their interview, patients provided information about their levels of self-care activities, including exercise, diet, and glucose testing. The interview provided multiple indicators of the personal-model constructs from which four composites were formed assessing cause, symptoms, treatment, and seriousness (a combination of course and consequences). In hierarchical multiple-regression analyses, these dimensions significantly improved the prediction of diet level and marginally improved the prediction of exercise after accounting for the effects of age and insulin taking. The results are discussed in terms of variations in personal models across different patient groups and diseases and the role of personal models in determining self-care behaviors.