To evaluate the association of hypomagnesemia with prehypertension (preHTN) and hypertension in children. A total of 3954 apparently healthy Mexican children were enrolled in a cross-sectional study. Exclusion criteria were type 2 diabetes; hepatic, renal, or endocrine disease; impaired fasting glucose; chronic diarrhea; and intake of vitamins or magnesium supplements in the previous 6 months. preHTN was defined by systolic and/or diastolic blood pressure ≥90th to