Introduction: The initial observations linking vitamin D to type 2 diabetes in humans came from studies showing that both healthy and diabetic subjects had a seasonal variation of glycemic control. Currently, there is evidence supporting that vitamin D status is important to regulate some pathways related to type 2 diabetes development. Based on available clinical and epidemiological data, the positive effects of vitamin D seem to be primarily related to its action on insulin secretion and sensitivity and secondary to its action on inflammation. Study design: This study was conducted on 70 subjects with age ranging from 33-68 years. They were divided into the following groups: Group І: 40 subjects with type 2 diabetes.Group ІІ: 30 healthy subjects as control. All the participants in the study were subjected to: History taking, Clinical examination, and Laboratory evaluation. Aim of study: To assess the relationship between serum 25-hydroxy vitamin D level and glycemic control in type 2 diabetic patients. Results: Diabetic patients had lower vitamin D with a mean level of 12.2±8.5 in comparison with the control subjects who had a mean level of 20.7±12.2 (P-value <0.01). Highly significant negative correlation between serum 25 (OH) Vit.D level and HbA1C, FPG & 2hour post-prandial plasma glucose and DM duration in type 2 diabetic group, moreover a highly significant negative correlation between serum 25 (OH) Vitamin D level and HbA1C in non diabetic control group (P value <0.001). Highly significant negative correlation between serum 25 (OH) Vit.D level and BMI in diabetic as well as control group (P value <0.001), with high significant negative correlation between serum 25 (OH) Vit.D level and metabolic syndrome in type 2 diabetes (P value = 0.02{<0.05}) as well as the whole studied subjects (P value <0.001). Conclusions: Diabetic patients had lower vitamin D level in comparison with the control subjects. The findings presented here have therapeutic implications. In patients with diabetes mellitus type 2, normal levels of vitamin D in the blood may facilitate glucose control. In addition, in people with a tendency to develop diabetes mellitus type 2, optimal levels of vitamin D within the blood may retard the clinical development of diabetes mellitus type 2.