There is evidence that an individual's health beliefs influence performance of health behaviors. The purpose of this study was to determine whether health beliefs in persons with diabetes could be modified during a clinical education program and whether the health beliefs were related to adherence to self-care instructions and metabolic control of diabetes. Health beliefs and HbA1c were measured at baseline in 189 adult outpatients with diabetes. Diabetes educators then attempted to modify health beliefs that were not conducive to positive health behaviors. Following education, some health beliefs were modified in a positive direction. Modest, but statistically significant increases in perceived severity of diabetes, perceived ability to carry out recommended behaviors, and perceived benefits of treatment were observed. Although HbA1c improved significantly in a subgroup of patients, this improvement could not be directly associated with any health belief or with self-reported adherence by the measures used in this study.