BACKGROUND: Dietary magnesium could modify the major stroke risk factors, high blood pressure (BP) and cholesterol, but has been understudied in both sexes in a single population. This study aimed to investigate if dietary magnesium intake was associated with BP, total cholesterol (TC) and incident stroke risk in an adult population. METHODS: We conducted cross-sectional analyses in a case-cohort study of 4443, men and women aged 40-75, representative of 25,639 participants years of the EPIC (European Prospective Investigation into Cancer)-Norfolk cohort. The cohort included 928 stroke cases (42,556.5 person years). Dietary data from 7 day food diaries were analysed using multivariate regression to assess associations between quintiles or data-derived categories of dietary magnesium intake and BP, TC and stroke risk, adjusted for relevant confounders. RESULTS: We observed differences of -7 mmHg systolic BP (P trend ≤ 0.01) and -3.8 mmHg diastolic BP (P trend=0.01) between extreme intakes of magnesium in men, a significant inverse association with TC was observed (P trend=0.02 men and 0.04 women). Compared to the bottom 10%, the top 30% of magnesium intake was associated with a 41% relative reduction in stroke risk (HR 0.59; 95% CI 0.38-0.93) in men. CONCLUSIONS: Lower dietary magnesium intake was associated with higher BP and stroke risk, which may have implications for primary prevention.