Capability of questionnaires to describe OHRQoL is varied in different countries. Based on assessments made in developed countries discriminant analysis capabilities of two questionnaires are different and GOHAI has a stronger correlation with function and masticatory ability; however, OHIP-14 can predict depression. In this context, no comparisons have been made between these two questionnaires in Persian-speaking countries. Therefore, the aim of this study was to evaluate the oral health of diabetic patients and their oral health-related quality of life (OHRQoL). Also through this study psychometric properties and discriminant analysis potential of two questionnaires were compared in patient with different oral health statuses and other diabetes-dependent conditions.