A tendency for Magnesium deficiency is commonly found in diabetic patients. The uncontrolled hyperglycemia and hyperglycuria in diabetic patients may increase magnesium excretion through osmotic diuresis, causing Magnesium depletion. The incidence of dental caries is higher in diabetic patients when compared to non-diabetics. Magnesium which has a PTH-mediated effect on Calcium might also be indirectly having a role to play in Calcium demineralization, increasing the susceptibility of teeth to dental caries. This study was a cross-sectional, comparative study undertaken to assess the serum calcium, magnesium levels, and dental caries in juvenile diabetic patients: - To assess the serum Magnesium level and it's relation to caries in children with or without juvenile diabetes;- To assess the serum Calcium level and it's relation to caries in children with or without juvenile diabetes;- To assess the ratio of Calcium: Magnesium and it's relation to caries in children with or withoutjuvenile diabetes.