The purpose of this study was to determine a possible association between magnesium intake and bone mass in young adult women. Subjects consisted of 106 female university students aged 19-25 years. Calcium and magnesium intakes were evaluated using the duplicate sampling method on three weekdays. Spinal and femoral bone mineral density (BMD) was measured by dual energy X-ray absorptiometry. Mean magnesium intake was 139 mg/day (median 127, SD 54). The correlation between magnesium intake and BMD was of borderline significance (r = 0.175, p = 0.073) for the femoral neck, and was insignificant (r = 0.084, p = 0.391) for the lumbar spine. However, the partial correlation between magnesium intake and BMD of the femoral neck (r = -0.027, p = 0.788), adjusted for calcium intake, was not significant. In conclusion, we did not find an association between magnesium intake and bone mass in young women, and calcium intake needs to be included as an important, potential confounding factor when exploring such an association.