This study was carried out to investigate the relationship between diabetic control and related factors of the practice of diet therapy which affects mostly diabetic patients’ dietary compliance. A questionnaire survey was conducted on 128 diabetic patients who had visited Internal medicine endocrinology clinic at University Medical Center of Daegu area. The questionnaires including clinical characteristics, meal regularity and food intake which shows dietary compliance, intrinsic barriers to the practice of diet therapy and knowledge of diet therapy were asked and analyzed. The factor which affects HbA1c was intrinsic barriers and HbA1c became higher as the level of intrinsic barriers was increasing. The education on diet therapy had no influence on the intrinsic barriers, but the level of knowledge on diet therapy was shown higher in the educated patients. The above results suggest that the practice of diet therapy should be leaded to develop behavioral aspects through resonable motivation on dietary compliance along with removing intrinsic barriers rather than simply providing information.