Background: Trace metals and Mg metabolism may play a role in adiposity which contributes to inflammation and oxidative stress; two potential mechanisms proposed to play a major role in the morbidity/mortality associated with obesity hence this study. Methods: We investigated trace metals-essential and toxic (Zn, Cu, Mn, Fe, Se, Cr, Pb, Cd and macro-metal Mg) in two hundred and sixty-four (264) subjects. They consist of group NONDH (60 non obese non diabetic/hypertensive or normal control); Group ONDH (45 Obese Non Diabetic/ Hypertensive- obese only), Group OD (59 Obese Diabetic); Group OH (59 Obese Hypertensive); Group ODH (41 Obese Diabetic/Hypertensive). Using standard procedures, weight, height, blood pressure and fasting blood glucose were measured and mineral trace metals and macro-metal Mg were analyzed spectrophotometrically. Results: showed that Obesity has a diminution effect on trace metals and Mg and obesity-associated complications (diabetes mellitus/hypertension) worsen this effect. Also Trace metals and Mg correlated positively with BMI in the obesity only subjects. But as soon as complications develop (OD and OH groups), the metals correlated negatively showing that the levels of the metals may be a useful biomarker in determining when obesity-associated complication(s) develop(s). Also All metals correlated negatively in obese non complicated (ONDH) and control (NONDH) groups with age showing that as age advances, there is reduction in the levels of trace metals and macro-metal Mg. Conclusion: These trace metals and macro-metal Mg studied may be probable useful biomarkers for identifying when obesity associated complications develops.