Experimental animal model studies have shown neuroprotective properties of magnesium. We assessed the relationship between admission magnesium and admission stroke severity and 3-month clinical outcomes in patients with acute intracerebral hemorrhage (ICH). The present study included 323 patients with acute ICH who were prospectively identified. Demographic characteristics, lifestyle risk factors, NIHSS score, hematoma volumes, and other clinical features were recorded at baseline for all participants. Patients was divided into three groups based on the admission magnesium levels (T1: <0.84; T2: 0.84-0.91; T3: ≥0.91 mmol/L). Clinical outcomes were death, poor functional outcome (defined by modified Rankin scale [mRS] scores 3-6) at 3 months. After 3-month follow-up, 40 (12.4%) all-cause mortality and 132(40.9%) poor functional outcome were documented. Median NIHSS scores for each tertile (T1 to T3) were 8.0, 5.5, and 6.0, and median hematoma volumes were 10.0, 8.05, and 12.4 ml, respectively. There are no significant association between baseline NIHSS scores(P=0.176) and hematoma volumes(P=0.442) in T3 and T1 in multivariable linear regression models. Compared with the patients in T1, those in T3 were associated with less frequency of all-cause mortality [adjusted odds ratio (OR), 0.10; 95% confidence interval (CI), 0.02-0.54; P-trend=0.010] but not poor functional outcome (adjusted OR, 1.80; 95%CI, 0.71-4.56; P-trend=0.227) after adjustment for potential confounders. Elevated admission serum magnesium level is associated with lower odds of mortality but not poor functional outcome at 3 months in patients with acute ICH. Copyright? Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.