The purpose of this study was to examine the psychometric properties of the recently developed Multidimensional Diabetes Questionnaire (MDQ). The MDQ, which is theoretically linked to a social learning perspective of diabetes, was designed to provide a comprehensive assessment of diabetes-related cognitive and social factors. It includes 41 items grouped into three sections: (1) perceptions related to diabetes and related social support, (2) positive and misguided reinforcing behaviors related to self-care activities, and (3) self-efficacy and outcome expectancies. Confirmatory factor analyses, conducted on a sample of 249 patients with non-insulin-dependent diabetes mellitus, supported the construct validity of the MDQ. Adequate internal consistency and significant demographic, psychological, behavioral, and disease-related correlates were found. The MDQ may prove valuable in understanding individual differences in adjustment to diabetes.