Aims: This study was designed to examine the relationship between vitamin D level and leptin level, and their effect on glycemic control in T2DM patients. Method: 366 blood samples (leftover) were taken from T2DM patients according to certain inclusion and exclusion criteria. Their vitamin D, leptin and HbA1c levels were measured. Results: The results of the tests showed that the presence of a deficiency in the level of vitamin D in T2DM patients is accompanied by a rise in the HbA1c test result (p=0.000), as well as an increase in leptin accompanied by an increase in the HbA1c test result (p=0.002), and also indicated that a low level of vitamin D is accompanied by a high level of leptin (p=0.041). Conclusions: Diabetic patients who have a deficient in vitamin D have poor glycemic control as well as obese patients who have high levels of leptin. Commitment to taking vitamin D by T2DM patients suffering from vitamin D deficiency reduces the value of HbA1c and thus improves the ability to control blood sugar.