Background: Osteoporosis is an important physiological change in elderly post-menopause ladies. It can induce a lot of complications such as hip fracture. Similar to serum calcium and phosphorus, serum magnesium is decreased in the osteoporosis women. Objective: In this study, evaluation of serum magnesium levels among diabetic osteoporosis-risk Sudanese pre-menopause ladies comparing to control group was carried. Materials: A total of 100 female, 50 low risk control subjects and 50 osteoporosis-risk female (25 with uncomplicated diabetes mellitus and 25 with other risks) were included in this study. Methods: Serum magnesium estimation was performed by AAS method. Results: There was no significant difference in serum Mg level between control group (0.90 mmol/L) and osteoporosis-risk (0.89mmol/L) groups (p > 0.05) while a significant differences were presented between control group (0.87mmol/L) and osteoporosis-risk ladies in diabetic (0.93 mmol/L) groups (p < 0.05) in this study. Conclusion: The serum magnesium level cannot be used as osteoporosis marker for pre-menopausal ladies