BACKGROUND, AIMS: There are biological associations between diabetes control and oral infections. We have also found psychological associations between diabetes self-care and oral health behavior. The aim of this study was to evaluate whether self-esteem can determine diabetes adherence and oral health behavior, both of with require daily, persistent self-care. METHOD: Cross-sectional data on 149 IDDM patients was collected by means of a quantitative self-completed questionnaire. RESULTS: High self-esteem was found to relate to good adherence with exercise regimens (p=0.005) and adjustment of insulin doses (p=0.040). These associations were also found when standardized for socio-demographic variables and HbA1c-level. In the dental sphere, logistic regression analysis showed an association between self-esteem and frequency of tooth brushing. CONCLUSIONS: It can be concluded that self-esteem may be a common psychological factor influencing diabetes and dental self-care. Strengthening patients' self-esteem could help patients to maintain daily self-care.