Individuals with type II diabetes mellitus use dietary supplements on a regular basis. The aim of study was to investigate the therapeutic effect of magnesium supplementation on glycemic control and lipid profile in adult type II diabetes mellitus patients. Seventy type II diabetes patients were allocated into: The intervention group (n=35) was received oral Magnesium oxide 250 mg once daily, and the control group (n=35) was received corn starch as a placebo. The duration of treatment for both groups was two months. After 2 months, the magnesium treated group demonstrated a significant reduction in FSG, HbA1c%, VLDL-C and triglyceride level, while insignificant change in TC, LDL-C and HDL-C, when compared to their pre-supplementation levels and the control group. There is no statistically significant difference between the two studied groups in the mean of age, BMI, systolic and diastolic blood pressure. The intervention group had a significant reduction in FSG (p= 0.034), HbA1c% level was significantly reduced in the magnesium treated group (p = 0.01) while in the control group HbA1c level is increased. Serum triglyceride levels decreased significantly (p < 0.05) in the magnesium supplemented group, but it is increased in the control group (p=0. 54). Oral magnesium supplementation has been shown to be effective in lowering glycaemic control and serum triglyceride level in patients with type 2 diabetes mellitus, and thus may be used as adjuvant therapy for management of patients with type II diabetes mellitus.