Over the past few decades, quality of life (QOL) has become an important concept in medical researches and treatments. Different meaningful reasons are given for this development. In the current research two standard questionnaires for evaluating of QOL were selected. First one, was a questionnaire from The World Health Organization (WHOQOL-BREF 26) and the second one, The Iranian Diabeticsʹ Quality of Life (IRDQOL). The goal of this study is to assess the relation between different domains of these questionnaires and HbA1c in diabetics. A random sample of Iranian adult outpatient diabetics (n=76) was selected and they completed the WHOQOL and IRDQOL assessment instruments. In addition HbA1c was measured in these patients by calorimetric method. Comparisons were made between scores of "questionnairesʹ domains" and "HbA1c". Data analysis was carried out by the use of T-test, Spearman correlation coefficient, Pearsonʹs correlation coefficient, and non-parametric statistical methods including Spearman correlation coefficient. Data analysis shows Psychological domain score in IRDQOL is lower than in WHOQOL and it is significant (P